D-penicillamine therapy of acute arsenic poisoning

Ammonium tetrathiomolybdate triggers autophagy-dependent NRF2 activation in vascular endothelial cells

Ammonium tetrathiomolybdate (TTM) is a copper chelator in clinical trials for treatment of Wilson's disease, tumors and other diseases. In the current study, we innovatively discovered that TTM is a novel NRF2 activator and illustrated that autophagy contributed to TTM-induced NRF2 activation. We showed that TTM treatment promoted NRF2 nuclear translocation and upregulated transcription level of NRF2 target genes including HMOX1, GCLM, and SLC7A11 in vascular endothelial cells (HUVECs). Moreover, NRF2 deficiency directly hindered TTM-mediated antioxidative effects. Followingly, we revealed that overexpression of KEAP1, a negative regulator of NRF2, significantly repressed NRF2 activation induced by TTM. Further mutation analysis revealed that KEAP1 Cys151 is a major sensor responsible for TTM-initiated NRF2 signaling, suggesting that KEAP1 is involved in TTM-mediated NRF2 activation. Notably, we found that TTM can trigger autophagy as evidenced by accumulation of autophagosomes, elevation of LC3BI-II/I, increase of LC3 puncta and activation of AMPK/mTOR/ULK1 pathway. Autophagic flux assay indicated that TTM significantly enhanced autophagic flux in HUVECs. Inhibition of autophagy with knockout of autophagy key gene ATG5 resulted in suppression of TTM-induced NRF2 activation. TTM also induced phosphorylation of autophagy receptor SQSTM1 at Ser349, while SQSTM1-deficiency inhibited KEAP1 degradation and blocked NRF2 signaling pathway, suggesting that TTM-induced NRF2 activation is autophagy dependent. As the novel NRF2 activator, TTM protected against sodium arsenite (NaAsO₂)-induced oxidative stress and cell death, while NRF2 deficiency weakened TTM antioxidative effects. Finally, we showed that autophagy-dependent NRF2 activation contributed to the protective effects of TTM against NaAsO₂-induced oxidative injury, because of ATG5 or SQSTM1 knockout aggravated NaAsO₂-induced elevation of HMOX1, cleaved PARP and γH2AX. Taken together, our findings highlight copper chelator TTM is a novel autophagy-dependent NRF2 activator and shed a new light on the cure for oxidative damage-related diseases.

Treatment of adult lead poisoning with D-penicillamine

Background The aim of the current study was to evaluate the efficacy of D-penicillamine in the treatment of lead poisoning mainly in the outpatient setting. Methods In a case series study performed during the recent epidemic of lead poisoning in Iran, lead-poisoned patients referring to our outpatient clinic were treated with 250-mg D-penicillamine capsules administered every 6 h for 5 or 10 days based on availability of the medication. They were recommended to re-check blood lead level (BLL) 4 weeks after cessation of the treatment and refer to our clinic again. Results In 63 patients with lead poisoning but without signs and symptoms of lead encephalopathy, median BLL was 106 [84, 131] μg/dL on presentation, which declined to a mean of 52.6 ± 28.8 μg/dL after a median treatment period of 7 [5, 10] days (p < 0.001). There was no statistically significant difference between the 5- and 10-day treatment protocols regarding complications and recovery. Treatment had resulted in a median decrease of 54 μg/dL [33, 90] (range: -20 to 231 μg/dL) in the patients' BLLs (33.9% declined in BLL measurements; range: -29.69% to 99.06%). Conclusions D-penicillamine may be an acceptable substitute treatment in adult lead poisoning. Although our sample size was limited, we could not detect any serious adverse effects in our cases showing that D-penicillamine resulted in acceptable recovery rates. This may be helpful especially in epidemics with limitations in antidote access.

Chronic arsenic poisoning following ayurvedic medication

BACKGROUND

Ayurveda, Indian traditional system of medicine, is practiced commonly in South East Asia and in many parts of the world. Many ayurvedic drugs contain heavy metals and may lead to metal toxicity. Of these, chronic lead poisoning is the most common. Chronic arsenic poisoning following the use of ayurvedic medication, though reported, is rare.

CASE REPORTS

We describe three patients who presented with features of chronic arsenic poisoning following prolonged ayurvedic medication use. The diagnosis of chronic arsenic poisoning was confirmed by high arsenic levels in the blood, urine, hair, and nails in all the three patients and in ayurvedic drug in two patients. The ayurvedic medication was discontinued and treatment with D-penicillamine started. At 6 months after treatment, blood arsenic levels returned to normal with clinical recovery in all of them.

CONCLUSION

Arsenic poisoning following ayurvedic medication is much less common than lead poisoning, though mineral ayurvedic medicines may lead to it. We used D-penicillamine as chelator and all of them recovered. Whether withdrawal of medication alone or D-penicillamine also played a role in recovery is unclear and needs to be assessed.

Depilatory Agents intoxication and factors contributing to its mortality: a 9-year review

Poisoning with depilatory agents is a rather uncommon entity in western countries. In this study, we describe poisoning with a corrosive arsenic-based depilatory agent (CABD) and factors related to its mortality in a poisoning center in Tehran. In a retrospective study, the medical records of all patients with CABD intoxication who attended the emergency ward of Loghman-Hakim hospital, the only poisoning center in Tehran, over a 9-year period between 2000 and 2009 were reviewed. The majority of patients were men (78.7%, n = 122 vs. women: 21.3%, n = 33). The mean age was 35.55 ± 16.68 years. Mean time of arrival to hospital was 3.63 hours (SD = 4.07). The mortality rate was 5.8% and increased significantly with higher amounts of ingestion and delay in arrival to hospital. CABD poisoning may be lethal if not treated promptly and correctly. Restriction or, if not practical, reduction of harmful components of this substance should be considered.

Heavy metal toxicity, Part I: arsenic and mercury

This review is Part I of a two-part series focusing on heavy metal toxicity. Part I will cover arsenic and mercury toxicity. Acute and chronic arsenic toxicity, as well as arsine gas toxicity, will be reviewed. The clinical presentation, with focus on the nervous, cardiovascular, pulmonary, gastrointestinal, hepatic, renal, hematopoietic, and dermatologic systems, is delineated. Mercury exposure, including exposure to short chain alkyl mercury, elemental mercury, and acute inorganic salt, is reviewed. The discussion of clinical toxicity focuses on the nervous, cardiovascular, pulmonary, gastrointestinal, and renal systems, as well as on the teratogenic effects of mercury. Recommendations for diagnostic tests and management plans are discussed, including chelation regimens.

Resistance mechanisms to arsenicals and antimonials

Salts and organic derivatives of arsenic and antimony are quite toxic. Living organisms have adapted to this toxicity by the evolution of resistance mechanisms. Both prokaryotic and eukaryotic cells develop resistance when exposed to arsenicals or antimonials. In the case of bacteria resistance is conferred by plasmid-encoded arsenical resistance (ars) operons. The genes and gene products of the ars operon of the clinically-isolated conjugative R-factor R773 have been identified and their mechanism of action elucidated. The operon encodes an ATP-driven pump that extrudes arsenite and antimonite from the cells. The lowering of their intracellular concentration results in resistance. Arsenate resistance results from the action of the plasmid-encoded arsenate reductase that reduces arsenate to arsenite, which is then pumped out of the cell.

Clinical observations and medical outcome in 149 cases of arsenate ant killer ingestion

One hundred forty-nine (149) consecutive cases of arsenate-containing ant killer reported to the Minnesota Regional Poison Center over 4 1/2 months were retrospectively reviewed with a follow-up (1 week to 3 months) completed in 132 (89%) of the population studied. One hundred and forty eight (99%) of the ingestions were accidental. The majority of cases involved children 3 years of age and younger. Only three patients accidentally ingesting the product were symptomatic (mild episodes of vomiting and diarrhea which cleared in all patients within 12 hours). No patient was referred to a medical center for treatment and no patient reached on follow-up reported any additional ill effects as a result of the exposure. In addition to the 149 patients in this series, we describe two representative patients who accidentally ingested similar amounts of sodium arsenate-containing ant killer, resulting in urine arsenic of 3500 micrograms/24 h and 5819 micrograms/24 h. They required no chelation treatment and had no evident sequelae during 4-6 months of medical follow-up. This experience supports poison center directed home management for the majority of single, acute, and accidental ingestions of small quantities (< 5 mL) of arsenate-containing ant killers as a safe alternative to medical center referral and adverse reactions to chelation.

Immunotherapy in acute arsenic poisoning

We investigated the use of immunotherapy on the treatment of sodium arsenite toxicity. Female balb/c mice injected with arsanilic acid conjugated to a carrier protein (ovalbumin) were shown to produce antibodies (arsenic reactive serum, ARS) reactive with arsanilic acid and sodium arsenite. Serum was tested for anti-ARS antibodies using a solid phase radioimmunoassay. The antisera bound to ARS conjugated to the synthetic copolymer glutamic acid60 tyrosine30 when diluted as high as 1:4096. Following multiple injections of 100 micrograms of arsanilic acid--ovalbumin compound, mortality on injection with sodium arsenite 0.87 mg/kg i.p. one week later decreased to 0 deaths in 22 pretreated mice vs 9 deaths in 29 untreated mice (31% mortality; p less than .005). No decrease in mortality was noted at higher challenges (1.15 mg/kg) of sodium arsenite. Antisera from pretreated mice was injected 0.1 cc i.p. into 12 week old female balb/c mice followed by an injection of sodium arsenite 0.87 mg/kg i.p. at 10 minutes. Again a protective effect was observed with 0 deaths in 18 mice vs eight deaths in 21 mice (38%; p less than .005). Seventeen additional mice were given an injection of 0.87 mg/kg i.p. of sodium arsenite. After 30 minutes, all mice became symptomatic whereupon antisera 0.1 cc i.p. was given. The one day mortality (2/17, 12%) was possibly lower than the combined control mortality (17/50, 34%; p less than 0.07). There was no change in mortality noted when antisera was administered to mice acutely exposed to 5 mg/kg HgCl2.

Effect of some arsenic antagonists on the toxicity, distribution and excretion of arsenite and arsenate in rats

1. Arsenite and arsenate poisoned rats were treated with either BAL (2,3-dimercapto-1-propanol), penicillamine (PA) (beta-beta dimethyl cystein) or selenium (Se) (as sodium selenite). 2. The minimal dose of each antagonist that treated arsenic-induced lethality (causing 100% survival) was the same for both arsenite and arsenate. 3. Arsenic mobilization from the tissues (blood, kidney, liver, lungs, spleen, muscles, brain, heart) and its excretion in urine and feces were higher in arsenite-intoxicated animals than in arsenate-intoxicated ones. 4. The effect of each antagonist, when injected alone, on the urinary and fecal excretion of endogenous metals (Cu, Zn, Fe, Ca and Mg) was also examined. 5. The results indicated marked differences in the relative ability of BAL, PA and Se to increase the excretion of the metals.

Survival following massive arsenic ingestion

A case of a 30-year-old man who ingested a massive quantity of arsenic (approximately 2,150 mg) in an apparent suicide attempt is presented. Aggressive initial therapy, including fluid resuscitation, chelation therapy, and hemodialysis, resulted in the patient's survival. The successful management of arsenic intoxication requires both prompt recognition and the initiation of specific and aggressive therapeutic modalities.

Arsenic poisoning. Ongoing diagnostic and social problem

Arsenic, commonly found in insecticides, herbicides, and industrial materials, is involved in the majority of heavy metal poisonings reported in the United States. Accidental poisoning appears to be most common in the pediatric age-group, whereas intentional and covert poisonings predominate in adults. Diagnosis is often difficult. The clinical presentations of arsenic poisoning, both acute and chronic types, represent a wide spectrum, largely dependent on route of exposure, chemical form, and dose. Because the patient or others providing the history may suppress information on exposure and because toxic levels of arsenic in the system drop rapidly in the first 24 hours, swift administration of diagnostic tests is important. Physician follow-up is determined by the route of exposure to arsenic and may involve referral to a social service network or a mental health facility.

Physical assessment and differential diagnosis of the poisoned patient

The rapid diagnosis and immediate intervention required in patients with serious drug overdose or poisoning makes toxicological screening of limited value to the emergency department physician. Instead, a careful clinical evaluation using the history, physical examination, and the more readily available laboratory tests may allow a tentative diagnosis and the initiation of life-saving treatment. Laboratory tests should include serum osmolality, electrolytes, glucose, BUN and an estimation of the anion and osmolar gaps. The ECG can also provide useful information. Clinical findings of important include altered blood pressure, pulse, respiration and body temperature, the presence of coma, agitation, delirium or psychosis, and muscular weakness. An ophthalmological examination is also of importance in the acutely poisoned patient. Oral burns or dysphagia may occur following ingestion of any strongly reactive substance, but the absence of oral burns does not preclude the possibility of oesophageal or stomach injury. Odours and skin colour may also contribute to the diagnosis. Comprehensive toxicology screening may not be immediately available, or may be inaccurate, thus adding little to the information obtained during the initial evaluation of the poisoned patient.

Unusual manifestations of arsenic intoxication

A patient with arsenic intoxication is reported, who presented with a variety of gastrointestinal and neurologic disturbances including unilateral facial nerve palsy and acute symptomatic pancreatitis, neither of which have been previously described as sequelae of arsenic poisoning. The patient also suffered hematologic, dermatologic, and cardiopulmonary complications. A review of the literature about this interesting problem is also presented.

Biological chelation: 2,3-dimercapto-propanesulfonic acid and meso-dimercaptosuccinic acid

Water soluble analogs of British Anti-Lewisite that are active orally and less toxic than BAL are now available. These agents are 2,3-dimercapto-1-propanesulfonic acid and meso-dimercaptosuccinic acid. Evidence for their effectiveness in preventing the lethal effects of sodium arsenite in mice and lewisite in rabbits is presented. These analogs can be expected to replace BAL in the treatment of heavy metal poisoning.

Subacute arsenic neuropathy: clinical and electrophysiological observations

Two patients with subacute arsenic neuropathy are described and the results of serial conduction velocity determinations from the very early stages of the illness to partial recovery are reported. Sensory and motor deficits were maximal within four weeks of the estimated time of exposure. Recovery was slow, with only partial improvement of the neurological deficits two years after onset of the illness. Progressive slowing of motor conduction velocity was observed in the first three months followed by a gradual increase in velocity thereafter. The possible mechanisms underlying the temporal profile of the electrophysiological changes are considered. The need for initiating chelation therapy before the development of the neuropathy is emphasised.

[D-Penacillamine. From constituent of penicillins to significant drug]

D-Penicillamine is used against a variety of diseases. For many years it has been successful in treating Wilson's disease, cystinuria and heavy-metal poisonings. It also proved to be effective against rheumatoid arthritis, scleroderma, chronic active hepatitis, pulmonary fibrosis and multiple sclerosis. However, the use of D-penicillamine is still limited owing to the frequent occurrence of considerable, though generally reversible, side effects. This article deals with the history of D-penicillamine as well as the methods of its synthesis, its pharmacokinetics, effects and side effects. In addition, the significance of the stereo isomeric L-penicillamine is discussed.