Mechanism underlying hypokalemia induced by trimethyltin chloride: Inhibition of H+/K+-ATPase in renal intercalated cells

Exposure to Trimethyltin Chloride Induces Pyroptosis and Immune Dysfunction in Grass Carp CIK Cells by Activating the NF-κB Pathway Through Oxidative Stress

Trimethyltin chloride (TMT) is a highly toxic organotin pollutant frequently found in aquatic environments, posing a significant threat to the ecological system. The kidney plays a vital role in the body's detoxification processes, and TMT present in the environment tends to accumulate in the kidneys. However, it remained unclear whether exposure to different doses of TMT could induce pyroptosis and immune dysfunction in grass carp kidney cells (CIK cells). For this purpose, after assessing the half-maximal inhibitory concentration (IC50) of TMT on CIK cells, we established a model for exposure of CIK cells at varying concentrations of TMT. CIK cells were treated with various doses of TMT (2.5, 5, 10 μM) for 24 h. Oxidative stress levels were measured using kits and fluorescence methods, whereas the expression of related genes was verified through western blot and quantitative real-time PCR (qRT-PCR). The results indicated that TMT exposure led to oxidative stress, with increased levels of ROS, H2O2, MDA, and GSH, and inhibited activities of T-AOC, SOD, and CAT. It activated the NF-κB pathway, leading to the upregulation of NF-κB p65, NF-κB p50, GSDMD, NLRP3, ASC, and Caspase-1. Furthermore, TMT exposure also resulted in increased expression of cytokines (IL-18, IL-6, IL-2, IL-1β, and TNF-α) and decreased expression of antimicrobial peptides (LEAP2, HEPC, and β-defensin). In summary, exposure to TMT induces dose-dependent oxidative stress that activates the NF-κB pathway, leading to pyroptosis and immune dysfunction in grass carp CIK cells.

Melatonin ameliorates trimethyltin chloride-induced cardiotoxicity: The role of nuclear xenobiotic metabolism and Keap1-Nrf2/ARE axis-mediated pyroptosis

Trimethyltin chloride (TMT) is a stabilizer for polyvinyl chloride plastics that causes serious health hazards in nontarget organisms. Melatonin (MT) exhibits powerful protective effects in cardiac diseases. As a new environmental pollutant, TMT-induced cardiotoxicity and the protective effects of MT remain unclear. To explore this, the mice were treated with TMT (2.8 mg/kg) and/or MT (10 mg/kg) for 7 days. Firstly, the histopathological and ultrastructural evaluation showed that TMT induced cardiac damage, tumescent rupture and nuclear pyknosis. Moreover, TMT elevated the expressions of pyroptosis genes NLRP3, ASC and Cas1 and inflammation factors IL-6, IL-17 and TNFα. Secondly, TMT reduced antioxidant enzymes (GSH, CAT and T-AOC) via decreasing the expression of genes associated with the Keap1-Nrf2/ARE pathway to increase oxidative stress. Thirdly, TMT decreased the expression of genes associated with the ARE-driven drug metabolizing enzymes (DMEs), including Akr7a3, Akr1b8, and Akr1b10. Besides, TMT upregulated the mRNA expression of nuclear Xenobiotic metabolism on cytochrome P450s enzymes via increasing the expression of CAR, PXP, and AHR genes. Furthermore, MT treatment mitigated the aforementioned adverse changes induced by TMT. Overall, these results demonstrated that TMT caused pyroptosis and inflammation to aggravate cardiac damage via inducing excessive oxidative stress, imbalance of DMEs homeostasis, and nuclear Xenobiotic metabolism disorder, which could be alleviated by MT.

TMT induces apoptosis and necroptosis in mouse kidneys through oxidative stress-induced activation of the NLRP3 inflammasome

Trimethyltin chloride (TMT) is an organotin heat stabilizer that is widely used in the production of plastics, and has strong toxicity. Here, the effect of trimethyltin chloride on mouse kidneys and its related mechanism were studied by taking TMT mouse with drinking water as a model. Histological examination and TUNEL results showed that the trimethyltin chloride group had typical apoptosis and necroptosis characteristics. Therefore, the level of oxidative stress was detected,and the expression of related genes was verified by real-time quantitative polymerase chain reaction (qRT-PCR) and Western blot methods. The results showed that oxidative stress was activated (MDA,SOD,CAT,T-AOC), released ROS, activated NF-κB pathway,activated inflammasome (NLRP3,Caspase-1,ASC), and inflammasome-secreted inflammatory factors (IL-1β). The expression of apoptosis (BCL-2, BAX, Caspase-3, Caspase-9) and necroptosis (RIPK1, RIPK33, MLKL, Caspase-8) increased.In addition, HEK293T human embryonic kidney cells were treated with trimethyltin chloride, and the results were similar to the tissue. In conclusion, TMT can induce oxidative stress, activate NF-κB pathway, and induce apoptosis and necroptosis through inflammasomes.

The main mechanisms of trimethyltin chloride-induced neurotoxicity: Energy metabolism disorder and peroxidation damage

Trimethyltin chloride (TMT) is a by-product in the synthesis of organotin, a plastic stabilizer. With the rapid development of industry, the occupational hazards caused by TMT cannot be ignored. TMT is a typical neurotoxicant, which mainly damages the limbic system and brainstem of the nervous system. Previous studies have demonstrated that the neurotoxicity induced by TMT is linked to the inhibition of energy metabolism, but the underlying mechanism remains elusive. In order to investigate the mechanism of TMT-induced inhibition of energy metabolism, C57BL/6 male mice were administered by IP injection in different TMT doses (0 mg/kg, 1.00 mg/kg, 2.15 mg/kg and 4.64 mg/kg) and times (1d, 3d and 6d), and then the changes of superoxide dismutase (SOD) activity, malondialdehyde (MDA) level and Na+-K+-ATPase activity in cerebral cortex, cerebellum, hippocampus, pons, medulla oblongata of mice, the expressions of Na+-K+-ATPase protein, AMP-activated protein kinase (AMPK), phosphorylated AMP-activated protein kinase(p-AMPK)and peroxisome proliferator-activated receptor γ coactivator-1 α (PGC-1α) in hippocampus and medulla oblongata were measured; the effects of TMT on the viability, the activity of SOD, glutathione (GSH) and Na+-K+-ATPase, MDA level, and the expression of PGC-1α and Na+-K+-ATPase protein in N2a cells were measured by different TMT doses and times, in order to verify the experiments in vivo. Our results found that most of the mice showed depression, tremor, epilepsy, spasm and other symptoms after TMT exposure. Moreover, with the increase of TMT dose, the activity of Na+-K+-ATPase and the expressions of AMPK protein in the hippocampus and medulla oblongata of mice decreased, and the expressions of p-AMPK protein increased. Peroxidative damage was evident in hippocampus, medulla oblongata of mice and N2a cells, and the expression of PGC-1α and Na+-K+-ATPase protein was significantly down-regulated. Therefore, it is reasonable to believe that TMT-induced neurotoxic symptoms and inhibition of energy metabolism may be related to p-AMPK and down-regulation of PGC-1α in the hippocampus and medulla oblongata.

Gastric H+/K+-ATPase Expression in Normal Laryngeal Tissue and Laryngeal Carcinoma

Background

Several studies have suggested that laryngopharyngeal reflux disease (LPRD) or gastroesophageal reflux disease (GERD) is an independent risk factor for laryngeal carcinoma. However, it remains unclear whether either condition affects the level of H⁺/K⁺-ATPase expression in laryngeal carcinoma.

Materials and Methods

Immunohistochemistry, real-time RT-PCR, and Western blotting were used to explore the distributions of proton pump (H⁺/K⁺-ATPase) α- and β-subunits in normal laryngeal tissue and laryngeal carcinoma.

Results

Messenger RNAs encoding both the α- and β-subunits were found in the normal epiglottic, ventricular fold, vocal fold, and arytenoid mucosae, as well as epiglottic cartilage. The distributions and expression levels of H+/K+-ATPase α-subunits in various laryngeal subregions did not significantly differ in IHC, RT-PCR, or Western blotting. However, Western blotting revealed a significant difference between the expression level of the β-subunit protein in the epiglottic cartilage and the levels in other sites. The expression levels of both subunits were significantly higher in carcinomatous than in paracarcinomatous tissue and normal laryngeal tissue. The mean follow-up duration was 66.2 months (range, 17–162 months). In all, 4 patients died during follow-up, 4 were lost to follow-up, and 22 were alive and free of disease at the end of follow-up. Two patients developed lung metastases and six developed disease recurrences (at 2, 8, 14, 16, 36, and 41 months). The 3- and 5-year overall survival (OS) rates were 93.0% and 77.0%, respectively. Univariate analyses showed that the 5-year OSs were significantly associated with the T, N, and clinical stages but not with age, alcohol use, pathological differentiation, or the expression levels of the α- or β-subunits (as revealed by IHC, RT-PCR, or Western blotting). However, in multivariate regression analyses, the 5-year OSs were not significantly associated with any clinicopathological factor or the expression levels of either subunit.

Conclusion

H⁺/K⁺-ATPase is expressed in the normal larynx, including in the epiglottic cartilage and the mucosae of the epiglottis, ventricular fold, and arytenoid vocal fold. The expression levels of the H⁺/K⁺-ATPase α- and β-subunits in laryngeal carcinomas were higher than in normal laryngeal tissues.

Autophagy in trimethyltin-induced neurodegeneration

Autophagy is a degradative process playing an important role in removing misfolded or aggregated proteins, clearing damaged organelles, such as mitochondria and endoplasmic reticulum, as well as eliminating intracellular pathogens. The autophagic process is important for balancing sources of energy at critical developmental stages and in response to nutrient stress. Recently, autophagy has been involved in the pathophysiology of neurodegenerative diseases although its beneficial (pro-survival) or detrimental (pro-death) role remains controversial. In the present review, we discuss the role of autophagy following intoxication with trimethyltin (TMT), an organotin compound that induces severe hippocampal neurodegeneration associated with astrocyte and microglia activation. TMT is considered a useful tool to study the molecular mechanisms occurring in human neurodegenerative diseases such as Alzheimer's disease and temporal lobe epilepsy. This is also relevant in the field of environmental safety, since organotin compounds are used as heat stabilizers in polyvinyl chloride polymers, industrial and agricultural biocides, and as industrial chemical catalysts.

Organotin Compounds Toxicity: Focus on Kidney

Organotin compounds (OTs) are synthetic persistent organometallic xenobiotics widely used in several commercial applications. They exert well-described harmful effects in brain, liver, adipose tissue, and reproductive organs, as they are endocrine-disrupting chemicals (EDCs), but the effects in the kidneys are less known. The kidneys are especially vulnerable to environmental contaminants because they are a metabolizing site of xenobiotics, therefore, pollutants can accumulate in renal tissue, leading to impaired renal function and to several renal abnormalities. Individuals chronically exposed to OTs present a threefold increase in the prevalence of kidney stones. These compounds can directly inhibit H⁺/K⁺-ATPase in renal intercalated cells, resulting in hypokalemia, renal tubular acidity, and increased urinary pH, which is a known risk factor for kidney stones formation. OTs effects are not only limited to induce nephrolithiasis, its nephrotoxicity is also due to increased reactive oxygen species (ROS). This increase leads to lipid peroxidation, abnormal cellular function, and cell death. Combined, the enzymatic and non-enzymatic antioxidant defense systems become deficient and there is a consequent uncontrolled generation of ROS that culminates in renal tissue damage. Still, few epidemiological and experimental studies have reported renal impact correlated to OTs exposure. This lack of investigation of the complete effect of OTs in renal function and structure led us to perform this review reporting the main researches about this subject.

Trimethyltin-induced cochlear degeneration in rat

Trimethyltin (TMT) is an occupational and environmental health hazard behaving as a potent neurotoxin known to affect the central nervous system as well as the peripheral auditory system. However, the mechanisms underlying TMT-induced ototoxicity are poorly understood. To elucidate the effects of TMT on the cochlea, a single injection of 4 or 8 mg/kg TMT was administered intraperitoneally to adult rats. The compound action potential (CAP) threshold was used to assess the functional status of the cochlea and histological techniques were used to assess the condition of the hair cells and auditory nerve fibers. TMT at 4 mg/kg produced a temporary CAP threshold elevation of 25–60 dB that recovered by 28 d post-treatment. Although there was no hair cell loss with the 4 mg/kg dose, there was a noticeable loss of auditory nerve fibers particularly beneath the inner hair cells. TMT at 8 mg/kg produced a large permanent CAP threshold shift that was greatest at the high frequencies. The CAP threshold shift was associated with the loss of outer hair cells and inner hair cells in the basal, high-frequency region of the cochlea, considerable loss of auditory nerve fibers and a significant loss of spiral ganglion neurons in the basal turn. Spiral ganglion neurons showed evidence of soma shrinkage and nuclear condensation and fragmentation, morphological features of apoptotic cell death. TMT-induced damage was greatest in the high-frequency, basal region of the cochlea and the nerve fibers beneath the inner hair cells were the most vulnerable structures.

Tributyltin chloride induces renal dysfunction by inflammation and oxidative stress in female rats

Tributyltin chloride (TBT) is an organometallic pollutant that is used as a biocide in antifouling paints. TBT induces several toxic and endocrine-disrupting effects. However, studies evaluating the effects of TBT on renal function are rare. This study demonstrates that TBT exposure is responsible for improper renal function as well as the development of abnormal morphophysiology in mammalian kidneys. Female rats were treated with TBT, and their renal morphophysiology was assessed. Morphophysiological abnormalities such as decreased glomerular filtration rate and increased proteinuria levels were observed in TBT rats. In addition, increases in inflammation, collagen deposition and α-smooth muscle actin (α-SMA) protein expression were observed in TBT kidneys. A disrupted cellular redox balance and apoptosis in kidney tissue were also observed in TBT rats. TBT rats demonstrated reduced serum estrogen levels and estrogen receptor-α (ERα) protein expression in renal cortex. Together, these data provide in vivo evidence that TBT is toxic to normal renal function and that these effects may be associated with renal histopathology complications, such as inflammation and fibrosis.

Trimethyltin-induced hippocampal neurodegeneration: A mechanism-based review

Trimethyltin (TMT), a toxic organotin compound, induces neurodegeneration selectively involving the limbic system and especially prominent in the hippocampus. Neurodegeneration-associated behavioral abnormalities, such as hyperactivity, aggression, cognitive deficits, and epileptic seizures, occur in both exposed humans and experimental animal models. Previously, TMT had been used generally in industry and agriculture, but the use of TMT has been limited because of its dangers to people. TMT has also been used to make a promising in vivo rodent model of neurodegeneration because of its region-specific characteristics. Several studies have demonstrated that TMT-treated animal models of epileptic seizures can be used as tools for researching hippocampus-specific neurotoxicity as well as the molecular mechanisms leading to hippocampal neurodegeneration. This review summarizes the in vivo and in vitro underlying mechanisms of TMT-induced hippocampal neurodegeneration (oxidative stress, inflammatory responses, and neuronal death/survival). Thus, the present review may be helpful to provide general insights into TMT-induced neurodegeneration and approaches to therapeutic interventions for neurodegenerative diseases, including temporal lobe epilepsy.

Effect of Trimethyltin Chloride on Slow Vacuolar (SV) Channels in Vacuoles from Red Beet (Beta vulgaris L.) Taproots

In the present study, patch-clamp techniques have been used to investigate the effect of trimethyltin chloride (Met3SnCl) on the slow vacuolar (SV) channels in vacuoles from red beet (Beta vulgaris L.) taproots. Activity of SV channels has been measured in whole-vacuole and cytosolic side-out patch configurations. It was found that addition of trimethyltin chloride to the bath solution suppressed, in a concentration-dependent manner, SV currents in red beet vacuoles. The time constant, τ, increased significantly in the presence of the organotin. When single channel activity was analyzed, only little channel activity could be recorded at 100 μM Met3SnCl. Trimethyltin chloride added to the bath medium significantly decreased (by ca. threefold at 100 μM Met3SnCl and at 100 mV voltage, as compared to the control medium) the open probability of single channels. Single channel recordings obtained in the presence and absence of trimethyltin chloride showed that the organotin only slightly (by <10%) decreased the unitary conductance of single channels. It was also found that Met3SnCl significantly diminished the number of SV channel openings, whereas it did not change the opening times of the channels. Taking into account the above and the fact that under the here applied experimental conditions (pH = 7.5) Met3SnCl is a non-dissociated (more lipophilic) compound, we suggest that the suppression of SV currents observed in the presence of the organotin results probably from its hydrophobic properties allowing this compound to translocate near the selectivity filter of the channel.

Chronic trimethyltin chloride exposure and the development of kidney stones in rats

We recently reported that occupational exposure to trimethyltin (TMT) is a risk factor for developing kidney stones. To further examine the association between TMT exposure and the formation of kidney stones, we conducted a 180-day animal study and exposed the randomly grouped Sprague-Dawley (SD) rats to TMT in the drinking water at doses of 0, 8.2, 32.8 and 131.3 µg kg(-1) day(-1). Transient behavioral changes were observed in the high-dose group during the first 2 weeks of exposure. TMT exposure led to a significant dose-dependent inhibition of renal H(+)/K(+)-ATPase and an increase in urinary pH. In comparison to no kidney stones being identified in the control and the lowest dose group, 1 rat in the 32.8 µg kg(-1) day(-1) dose group and 3 out of 9 rats in the 131.3 µg kg(-1) day(-1) dose group were found to have stones in the kidney/urinary tract. Pathological analysis showed that more wide spread calcium disposition was observed in kidneys of rats with TMT exposure compared with the rats in the control group. However, X-ray diffraction (XRD) analysis found that the kidney stones were mainly composed of struvite with the formula: NH4MgPO4 6H2O, while calcium-containing components were also detected. Together, this study further demonstrates through animal studies that chronic exposure to a relatively low level of TMT induces nephrotoxicity and increases the risk for developing kidney stones.

Chronic low level trimethyltin exposure and the risk of developing nephrolithiasis

OBJECTIVES

Nephrolithiasis (kidney stones) is a common disease with the prevalence that is increasing globally. We previously found that trimethyltin (TMT), a by-product of plastic stabilisers, can inhibit the H(+)/K(+) ATPase activity in renal intercalated cells and alter urinary pH, which is a known risk factor for nephrolithiasis. In this study, we conducted a cross-sectional analysis to evaluate the impact of chronic low level occupational TMT exposure on nephrolithiasis.

METHODS

This study included 216 healthy workers with TMT exposure and 119 workers as controls with no TMT exposure. All study participants were administered a questionnaire and underwent a routine clinical examination including an ultrasonographic screening for kidney stones. Exposures were assessed by measuring TMT concentrations in personal air samples, blood and urine. Logistic regression analysis was used to estimate the ORs and 95% CIs for the risk of kidney stones.

RESULTS

TMT exposed workers had a higher prevalence of kidney stones (18.06%) in comparison with control workers (5.88%). High TMT concentrations in personal air samples, blood and urines were positively associated with increased prevalence of kidney stones in workers exposed to TMT compared with controls workers (p-trend values=0.005, 0.008 and 0.002, respectively). The length of employment in plants with elevated TMT levels (duration of the exposure) was significantly associated with the increased prevalence of kidney stones (p trend=0.001). The ORs were 2.66 for <3 years, 3.73 for 3-<10 years and 7.89 for 10+ years of employment compared with control workers.

CONCLUSIONS

To our knowledge, this is the first report to demonstrate that occupational exposure to TMT is a potential risk factor for nephrolithiasis.

Toxicity of trimethyltin and dimethyltin in rats and mice

Extensive uses of methyltin compounds in polyvinyl chloride (PVC) production have led to a dramatic increase of occupational-related methyltin poisoning accidents and the widespread contamination of methyltins in various environmental media. Here, we conducted studies to compare the acute toxicity induced by trimethyltin (TMT) and dimethyltin (DMT), and investigated the cumulative toxic effects of TMT in rats and mice. Neurobehavioral changes were observed in rats and mice treated with either DMT or TMT, but we also observed that both TMT and DMT exposure in rats significantly lowered the blood potassium level. Moreover, the cumulative toxic coefficient factor of TMT was 1.7 in rats versus 3.8 in mice, suggesting a high cumulative risk for rats and a moderate risk for mice. In summary, we demonstrated that acute and chronic exposure to methyltin compounds induced neurotoxicity and hypokalemia. Moreover, our study suggests that TMT can accumulate in the body and pose a risk for workers chronically exposed to a low dose of TMT.

Apoptosis induced by trimethyltin chloride in human neuroblastoma cells SY5Y is regulated by a balance and cross-talk between NF-κB and MAPKs signaling pathways

Trimethyltin chloride (TMT) has been known as a classic neurotoxicant which can cause serious neuronal degeneration diseases. Nuclear factor κB (NF-κB) and mitogen-activated protein kinases (MAPKs) signaling pathways play pivotal role in the central nerves system. In the present study, the intracellular pathways involved in TMT-induced apoptosis on human neuroblastoma cells SY5Y (SH-SY5Y) were investigated. We observed high level of nuclear NF-κB p65 submit, activated JNK, ERK, and p38 by TMT exposure. In contrast, low level of Bcl-2 and XIAP (two known NF-κB-regulated endogenous anti-apoptotic molecules) was present. To further investigate the role of these pathways and the relationship between them, specific inhibitors were used and the alteration of each pathway was evaluated. Pretreatment with MG132, an inhibitor of proteasome activity, and BAY11-7082, an inhibitor of IκBα phosphorylation, both inhibited NF-κB p65 translocation and significantly promoted apoptosis. NF-κB inhibition also induced down-expression of Bcl-2 and XIAP, exaggerated JNK phosphorylation, and ERK inhibition. SP600125 and U0126, by blocking the phosphorylation of c-Jun and MEK1/2, inhibited JNK and ERK phosphorylation, respectively, and attenuated apoptosis significantly. JNK and ERK inhibition also induced IκBα degradation and NF-κB p65 translocation, leading to expression of Bcl-2 and XIAP. The detrimental role of MG132 and BAY11-7082 appears related to the exaggerated JNK phosphorylation. The SP600125 and U0126 neuroprotection appears related to NF-κB-regulated transcriptional control of Bcl-2 and XIAP. These results suggest that the cross-talk and a balance between NF-κB and MAPKs may be involved in TMT-induced apoptosis on SH-SY5Y cells.

Early life stage trimethyltin exposure induces ADP-ribosylation factor expression and perturbs the vascular system in zebrafish

Trimethyltin chloride (TMT) is an organotin contaminant, widely detected in aqueous environments, posing potential human and environmental risks. In this study, we utilized the zebrafish model to investigate the impact of transient TMT exposure on developmental progression, angiogenesis, and cardiovascular development. Embryos were waterborne exposed to a wide TMT concentration range from 8 to 96 h post fertilization (hpf). The TMT concentration that led to mortality in 50% of the embryos (LC(50)) at 96 hpf was 8.2 μM; malformations in 50% of the embryos (EC(50)) was 2.8 μM. The predominant response observed in surviving embryos was pericardial edema. Additionally, using the Tg (fli1a: EGFP) y1 transgenic zebrafish line to non-invasively monitor vascular development, TMT exposure led to distinct disarrangements in the vascular system. The most susceptible developmental stage to TMT exposure was between 48 and 72 hpf. High density whole genome microarrays were used to identify the early transcriptional changes following TMT exposure from 48 to 60 hpf or 72 hpf. In total, 459 transcripts were differentially expressed at least 2-fold (P<0.05) by TMT compared to control. Using Ingenuity Pathway Analysis (IPA) tools, it was revealed that the transcripts misregulated by TMT exposure were clustered in numerous categories including metabolic and cardiovascular disease, cellular function, cell death, molecular transport, and physiological development. In situ localization of highly elevated transcripts revealed intense staining of ADP-ribosylation factors arf3 and arf5 in the head, trunk, and tail regions. When arf5 expression was blocked by morpholinos, the zebrafish did not display the prototypical TMT-induced vascular deficits, indicating that the induction of arf5 was necessary for TMT-induced vascular toxicity.

Trimethyltin chloride (TMT) neurobehavioral toxicity in embryonic zebrafish

Trimethyltin chloride (TMT) is a neurotoxicant that is widely present in the aquatic environment, primarily from the manufacture of PVC plastic, but few studies have evaluated aquatic neurotoxicity. We have examined TMT dose-dependent malformation and neurobehavioral toxicity in the embryonic zebrafish model. Exposure of embryos to TMT (0-10 μM) from 48 to 72 hours post fertilization (hpf) elicited a concentration-related increase (0-100%) in malformation incidence with an EC(25) of 5.55 μM. TMT also significantly modulated the frequency of tail flexion, the earliest motor behavior observed in developing zebrafish, and the ability to respond to a mechanical tail touch. Exposure to 5 μM TMT from 48 to 72 hpf modulated the photomotor response at 4 and 5 days post fertilization and significantly promoted apoptosis in the tail. Our study demonstrates the morphological and behavioral sensitivity of the developing zebrafish to TMT and establishes a platform for future identification of the affected pathways and chemical modulators of TMT toxicity.

Does a proton pump inhibitor cause hypokalemia?

Proton pump inhibitors (PPIs) act only in the stomach, although the proton pump, H(+),K(+)-ATPase exists and contributes to H(+) and K(+) homeostasis in the kidney. We encountered two hypokalemic cases receiving omeprazole. These cases were women ages 69 and 80 years old. Their serum potassium levels decreased with accelerated urinary potassium excretion with the use of omeprazole, and recovered by potassium-supplement and the discontinuation of omeprazole. Because inhibitory effects of PPIs on H(+),K(+)-ATPase are exerted only in acidic condition, hypokalemia is not generally introduced by PPIs alone. However, in extreme alkalosis or impaired K(+)-recycling system, PPIs may cause hypokalemia unrelated to hypomagnesemia.