An agonist of CXCR4 induces a rapid recovery from the neurotoxic effects of Vipera ammodytes and Vipera aspis venoms

People bitten by Alpine vipers are usually treated with antivenom antisera to prevent the noxious consequences caused by the injected venom. However, this treatment suffers from a number of drawbacks and additional therapies are necessary. The venoms of Vipera ammodytes and of Vipera aspis are neurotoxic and cause muscle paralysis by inducing neurodegeneration of motor axon terminals because they contain a presynaptic acting sPLA2 neurotoxin. We have recently found that any type of damage to motor axons is followed by the expression and activation of the intercellular signaling axis consisting of the CXCR4 receptor present on the membrane of the axon stump and of its ligand, the chemokine CXCL12 released by activated terminal Schwann cells. We show here that also V. ammodytes and V. aspis venoms cause the expression of the CXCL12-CXCR4 axis. We also show that a small molecule agonist of CXCR4, dubbed NUCC-390, induces a rapid regeneration of the motor axon terminal with functional recovery of the neuromuscular junction. These findings qualify NUCC-390 as a promising novel therapeutics capable of improving the recovery from the paralysis caused by the snakebite of the two neurotoxic Alpine vipers.

Hydrogen cyanamide exposure: a case series from Pavia Poison Control Centre

BACKGROUND

Hydrogen cyanamide is a plant growth regulator introduced in Italy as Dormex in 2000, but recalled from the market in 2008. It's currently not authorized in Europe. Inhalation/dermal contact may cause irritation/caustic burns, ingestion of severe organ damage and concomitant alcohol consumption disulfiram-like reaction due to aldehyde-dehydrogenase inhibition by hydrogen cyanamide.

AIMS

To study all exposure cases referred to our centre, evaluating temporal and geographic distribution and analysing clinical manifestations, including the ones after alcohol consumption.

METHODS

We retrospectively evaluated all hydrogen cyanamide exposures referred to our Poison Control Centre (January 2007-December 2021). For each case, age, sex, exposure route/year, geographical location, intent of exposure, alcohol co-ingestion, emergency department-admission Poison Severity Score, signs/symptoms and treatment were analysed.

RESULTS

Thirty subjects were included. Median case/year was 1 [1; 2]: 79% occurred after market withdrawal, 92% in Sicily. All exposures were unintentional and work related; 41% of patients also co-ingested alcohol. Mean poison severity score at emergency department admission was 1.54, more severe when ingestion occurred. The most common signs/symptoms were flushing, secondary to peripheral vasodilation (41%), hyperaemia/erythema (29%), dyspnoea (25%), nausea (20%), vomiting (12%), oedema (12%), II-III degrees burns (12%) and pharyngodynia (12%). All patients were treated symptomatically and fully recovered.

CONCLUSIONS

Hydrogen cyanamide exposure can lead to severe clinical manifestations. Despite its withdrawal from the Italian market, hydrogen cyanamide is still used: through PCC's crucial role in monitoring exposure to agricultural products efforts should be made to contrast illegal trade and increase awareness of its potential toxicity in those countries in which it's still legal.

Effect of the first wave of COVID-19 on Poison Control Centre activities in 21 European countries: an EAPCCT initiative

BACKGROUND

Public health emergencies often affect Poison Control Centre (PCC) operations. We examined possible effects of the coronavirus disease 2019 (COVID-19) pandemic on call volume, call characteristics, and workload in European PCCs.

METHOD

All 65 individual European PCCs were requested to supply data on the number of calls and call characteristics (caller, age groups, reason and specific exposures) from March to June in 2018, 2019, and 2020 (Part 1). Number of calls with specific characteristics was normalised to all calls. Calls (N) and call characteristics (%) were compared between 2020 and 2018/2019 (average), within PCCs/countries and grouped. Correlation between call volume and COVID-19 cases per PCC/country was examined. All PCCs received a survey on workload (Part 2). Parts 1 and 2 were independent.

RESULTS

For Part 1, 36 PCCs (21 countries) supplied 26 datasheets. PCCs in the UK and in France merged data and supplied one datasheet each with national data. Summed data showed an increase of 4.5% in call volume from 228.794 in 2018/2019 (average) to 239.170 in 2020 (p < 0.001). Within PCCs/countries, calls significantly increased for 54% of PCCs/countries (N = 14/26) and decreased for 19% (N = 5/26), three of which (N = 3/5) only serve medical professionals. Correlation between call volume and COVID-19 cases was (non-significant) positive (Rho >0.7) in 5/26 PCCs/countries (19%), and negative in 6/26 (23%). Call characteristics (median proportion of grouped data in 2018/2019 vs. 2020) changed: fewer medical professionals called (40 vs. 34%, p < 0.001), calls on intentional exposures decreased (20 vs. 17%, p < 0.012), as did calls on patients between 13 and 17 years (5 vs. 4%, p < 0.05). Calls on specific exposures increased; disinfectants from 1.9 to 5.2%, and cleaning products from 4.4 to 5.7% (p < 0.001). For Part 2, 38 PCCs (24 countries) filled the survey on workload (number/length of shifts and time on PCC duties), which increased in 23/38 PCCs (61%), while 10/38 (26%) worked with fewer employees.

CONCLUSIONS

Obtaining aggregated European PCC data proved challenging but showed an increase in overall call volume and workload during the first COVID-19 wave. Call characteristics changed including fewer calls from professionals and more calls on specific exposures. Within single PCCs/countries a variety of effects was observed.

MAM-2201, One of the Most Potent-Naphthoyl Indole Derivative-Synthetic Cannabinoids, Exerts Toxic Effects on Human Cell-Based Models of Neurons and Astrocytes

Considering the consequences on human health, in general population and workplace, associated with the use of new psychoactive substances and their continuous placing on the market, novel in vitro models for neurotoxicology research, applying human-derived CNS cells, may provide a means to understand the mechanistic basis of molecular and cellular alterations in brain. Cytotoxic effects of MAM-2201, a potent-naphthoyl indole derivative-synthetic cannabinoid, have been evaluated applying a panel of human cell-based models of neurons and astrocytes, testing different concentrations (1-30 µM) and exposure times (3-24-48 h). MAM-2201 induced toxicity in primary neuron-like cells (hNLCs), obtained from transdifferentiation of mesenchymal stem cells derived from human umbilical cord. Effects occurred in a concentration- and time-dependent manner. The lowest concentration affecting cell viability, metabolic function, apoptosis, morphology, and neuronal markers (MAP-2, NSE) was 5 μM, and even 1 μM induced apoptosis. Effects appeared early (3 h) and persisted after 24 and 48 h. Similar behavior was evidenced for human D384-astrocytes treated with MAM-2201. Differently, human SH-SY5Y-neurons, both differentiated and undifferentiated, were not sensitive to MAM-2201. On D384, the different altered endpoints were reversed, attenuated, or not antagonized by AM251 indicating that CB1 receptors may partially mediate MAM-2201-induced cytotoxicity. While in hNLCs, all toxic effects caused by MAM-2201 were apparently unrelated to CB-receptors since they were not evidenced by immunofluorescence. The present in vitro findings demonstrate the cytotoxicity of MAM-2201 on human primary neurons (hNLCs) and astrocytes cell line (D384), and support the use of these cellular models as species-specific in vitro tools suitable to clarify the neurotoxicity mechanisms of synthetic cannabinoids.

Neurotoxicity of European viperids in Italy: Pavia Poison Control Centre case series 2001-2011

CONTEXT

Some clinical aspects about neurotoxicity after snakebites by European viper species remain to be elucidated.

OBJECTIVE

This observational case series aims to analyze neurological manifestations due to viper envenomation in Italy in order to describe the characteristic of neurotoxicity and to evaluate the clinical response to the antidotic treatment, the outcome, and the influence of individual variability in determining the appearance of neurotoxic effects.

MATERIALS AND METHODS

All cases of snakebite referred to Pavia Poison Centre (PPC) presenting peripheral neurotoxic effects from 2001 to 2011 were included. Cases were assessed for time from bite to PPC evaluation, Grade Severity Score (GSS), onset/duration of clinical manifestations, severity/time course of local, non-neurological and neurological effects, and antidotic treatment.

RESULTS

Twenty-four were included (age, 3-75 years) and represented on average of 2.2 cases/year (about 5% of total envenomed patients). The mean interval time of PPC evaluation from snakebite was 10.80 ± 19.93 hours. GSS at ED-admission was 0 (1 case), 1 (10 cases), and 2 (13 cases). All patients showed local signs: 41.6%, minor; 58.4%, extensive swelling and necrosis. The main systemic non-neurological effects were as follows: vomiting (86.7%), diarrhea (66.7%), abdominal discomfort (53.3%), and hypotension (20%). Neurotoxic effects were accommodation troubles and diplopia (100%), ptosis (91.7%), ophtalmoplegia (58.3%), dysphagia (20.8%), drowsiness (16.6%), cranial muscle weakness (12.5%), and dyspnea (4.2%). Neurotoxicity was the unique systemic manifestation in 9 cases; in 4 cases, they were associated with only mild local swelling. In 10 patients the onset of neurotoxic effects followed the resolution of systemic non-neurological effects. Antidote was intravenously administered in 19 (79.2%) patients. The mean duration of manifestations in untreated versus treated groups was 53.5 ± 62.91 versus 41.75 ± 21.18 hours (p = 0.68, local effects) and 9.77 ± 3.29 versus 8.25 ± 12.23 hours (p = 0.1, systemic non-neurological effects) and 43.4 ± 14.69 versus 26.58 ± 20.62 hours (p = 0.03, neurotoxic effects).

CONCLUSIONS

Neurotoxicity may appear late (11 hours after the bite in 58.3% of cases), in contrast with the data reported in medical literature. Neurotoxic effects have been reversible in all cases and may be the unique systemic manifestation of envenomation. Neurotoxic effects are shorter in treated group. The antidotic treatment of patients considered as GSS 2 only for neurotoxic effects (with mild local effects) may not be necessary. Variable factors such as different amount of venom injected, concentration of PLA2 component, and individual susceptibility may explain the less percentage of patients presenting neurotoxic effects.

[Evidence of snakes in urban areas. Analysis of cases in the province of Cuneo and public health issues]

In this paper the authors analyse the cases of intrusion of snakes into urban environments in southern Piedmont (province of Cuneo) in the years 2010-2012 (up to may). In the study period there were 83 cases of intrusions in urban and domestic areas, mostly due to native harmless species (97.6%), while in 2.4% (n=2) of the cases alien species were responsible, and in 4.8% (n=4) poisonous native species were involved (Vipera aspis). The incidence of bites after a domestic intrusion is found to be 6% (n=5). All bites have resulted in loco-regional minor symptoms and occurred as a result of an accidental contact. In order to limit the risk of poisoning, the authors recommend the intrusions to be handled by properly trained personnel, since it can never be ruled out the presence of dangerous alien species on the national territory.

Web-based antidotes management: evaluation of an Italian experience

Antidotes (ANT) are lifesaving drugs that must be timely administered in case of poisoning, but their availability when and where needed is often a problem. The experience of setting up a web-based national network aimed at sharing ANT availability information is described, together with the steps followed to make it be an effective solution.