Exploring the association between two groups of metals with potentially opposing renal effects and renal function in middle-aged and older adults: Evidence from an explainable machine learning method.

BACKGROUND: Machine learning models have promising applications in capturing the complex relationship between mixtures of exposures and outcomes. OBJECTIVE: Our study aimed at introducing an explainable machine learning (EML) model to assess the association between metal mixtures with potentially opposing renal effects and renal function in middle-aged and older adults. METHODS: This study extracted data from two cycle years of the National Health and Nutrition Examination Survey (NHANES). Participants aged 45 years or older with complete data on six metals (lead, cadmium, manganese, mercury, and selenium) and related covariates were enrolled. The EML model was developed by the optimized machine learning model together with Shapley Additive exPlanations (SHAP) to assess the chronic kidney disease (CKD) risk with metal mixtures. The results from EML were further compared in detail with multiple logistic regression (MLR) and Bayesian kernel machine regression (BKMR). RESULTS: After adjusting for included covariates, MLR pointed out the lead and arsenic were generally positively associated with CKD, but manganese had a negative association. In the BKMR analysis, each metal was found to have a non-linear association with the risk of CKD, and interactions can exist between metals, especially for arsenic and lead. The EML ranked the feature importance: lead, manganese, arsenic and selenium were close behind in importance after gender, age or BMI for participants with CKD. Strong interactions between mercury and lead, manganese and cadmium and arsenic and manganese were identified by partial dependence plot (PDP) of SHAP and bivariate exposure-response effect plots of BKMR. The EML model determined the "trigger point" at which the risk of CKD abruptly changed. CONCLUSION: Co-exposure to metals with different nephrotoxicity could have different joint association with renal function, and EML can be a powerful method for studying complex exposure mixtures.

Lipid Polyunsaturated Fatty Acid Chains in Mouse Kidneys Were Increased within 5 min of a Single High Dose Whole Body Irradiation.

To understand the ultra-early reaction of normal organ lipids during irradiation, we investigated the response of lipids, including polyunsaturated fatty acid (PUFA) chains, which are particularly susceptible to damage by ROS, in mice's kidneys, lungs, brains, and livers within 5 min of single high-dose irradiation. In this study, we set up three groups of C56BL/6 male mice and conducted whole-body irradiation with 0 Gy, 10 Gy, and 20 Gy single doses. Kidney, lung, brain, and liver tissues were collected within 5 min of irradiation. PUFA-targeted and whole lipidomic analyses were conducted using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The results showed that PUFA chains of kidney phosphatidylcholine (PC), phosphatidylethanolamine (PE), and triacylglycerol (TG) significantly increased within 5 min of 10 Gy and 20 Gy irradiation. The main components of increased PUFA chains in PC and PE were C18:2, C20:4, and C22:6, and in TG the main component was C18:2. The kidney lipidomes also showed significant changes from the perspective of lipid species, mainly dominated by an increase in PC, PE, TG, and signal lipids, while lipidomes of the lung, brain, and liver were slightly changed. Our results revealed that acute PUFA chains increase and other lipidomic changes in the kidney upon whole-body irradiation within 5 min of irradiation. The significantly increased lipids also showed a consistent preference for possessing PUFA chains. The lipidomic changes varied from organ to organ, which indicates that the response upon irradiation within a short time is tissue-specific.

The effects of the water-soluble fractions of crude oil on liver and kidney tissues of Caspian Kutum juveniles, Rutilus frisii.

The lethal and histopathological impacts of crude oil's Water-Soluble Fraction (WSF) on the liver and kidney tissues of juvenile Rutilus frisii were investigated. The LC50 96 h of WSF was calculated at 33.95 ppm. Fish exposed to two concentrations (0.1 LC50 and LC50) of WSF and control for 24 and 96 h were used for histopathological studies. Tissues in the control group and 0.1 LC50-24 h were healthy, and no specific damages were observed. With increasing exposure time (96 h) and concentration (LC50), damages' type, frequency, and intensity gradually increased. Cloudy swelling, loss of cell boundary, nuclei deformation, and congestion of blood vessels were found in the liver, enlarged glomeruli, reduced Bowman's space, and occlusion of the tubular lumen, were found in the kidney. It is demonstrated that the WSF of crude oil can cause severe damage to the tissues of juvenile Kutum, depending on the exposure concentration.

Acute exposure of early-life stage zebrafish (Danio rerio) to Deepwater Horizon crude oil impairs glomerular filtration and renal fluid clearance capacity.

The pronephros (early-stage kidney) is an important osmoregulatory organ, and the onset of its function occurs relatively early in some teleost fishes. As such, any defects in kidney development and function are likely associated with a decreased ability to osmoregulate. Previous work has shown that early-life stage (ELS) zebrafish (Danio rerio) acutely exposed to Deepwater Horizon (DWH) crude oil exhibit transcriptional changes in key genes involved in pronephros development and function, as well as pronephric morphological defects and whole-animal osmoregulatory impairment. The objective of this study was to examine the acute effects of crude oil exposure during zebrafish ELS on pronephros function by assessing its fluid clearance capacity and glomerular filtration integrity. Following a 72-h exposure to control conditions, 20% or 40% dilutions of high-energy water-accommodated fractions (HEWAF) of DWH crude oil, zebrafish were injected into the common cardinal vein either with fluorescein-labeled (FITC) 70-kDa dextran to assess glomerular filtration integrity or with FITC-inulin to assess pronephric clearance capacity. Fluorescence was quantified after the injections at predetermined time intervals by fluorescence microscopy. The results demonstrated a diminished pronephric fluid clearance capacity and failed glomerular perfusion when larvae were exposed to 40% HEWAF dilutions, whereas only a reduced glomerular filtration selectivity was observed in zebrafish previously exposed to the 20% HEWAF dilution.

Efficacy of Yishen Huashi Granules Combined with Linagliptin Tablets on Blood Glucose and Renal Function in Patients with Type 2 Diabetic Nephropathy.

Objective: To probe into the efficacy of Yishen Huashi granules combined with linagliptin tablets in the treatment of type 2 diabetic nephropathy (DN) and its effect on blood glucose and renal function in patients. Methods: 70 patients with type 2 DN at our hospital between May 2020 and May 2022 were chosen as the research objects and separated into the control group and the research group based on their treatments. With 35 cases in each group, the patients treated with initial therapy and linagliptin tablets were enrolled in the control group, and those who received the above treatments and also Yishen Huashi granules were included in the research group. Their clinical indexes such as blood glucose and renal function were compared with both groups after treatment. Results: After treatment, the research group had remarkably lower fasting blood glucose (FPG), 2 h-postprandial blood glucose (2 h-PBG), and glycosylated hemoglobin A1c (HbA1c) levels than those in the control group (P < 0.05). After treatment, the research group had remarkably lower levels of total cholesterol (TC), triglyceride (TG), and low-density lipoprotein (LDL) (P < 0.05) and higher high-density lipoprotein (HDL) levels (P < 0.05) than those in the control group. After treatment, the urinary microalbumin (u-mALB) level was remarkably lower in both groups (P < 0.05) and was distinctly lower in the research group than in the control group (P < 0.05). After treatment, the research group had remarkably lower renal function indexes such as serum creatinine (SCr), blood urea nitrogen (BUN), urinary protein (UPro), and urinary albumin excretion rate (UAER) (P < 0.05) and a higher estimated glomerular filtration rate (eGFR) level (P < 0.05) than those in the control group. The efficacy was evaluated by the traditional Chinese medicine (TCM) syndrome score after treatment. There were no patients in complete remission between both the groups, where slight differences were found in the proportion of significant remission (P > 0.05), with the total effective rate of the research group remarkably higher than that of the control group (P < 0.05). Conclusion: The combination of Yishen Huashi granules and linagliptin tablets can reduce the blood glucose and blood lipid levels in patients with type 2 DN and lower UPro and protect renal function at the same time, which provides a new idea and a method for clinical treatment of type 2 DN with integrated traditional Chinese and Western medicine.

Discovery of potential active ingredients of Er-Zhi-Wan, a famous traditional Chinese formulation, in model rat serum for treating osteoporosis with kidney-yin deficiency by UPLC-Q/TOF-MS and molecular docking.

Er-Zhi-Wan (EZW), a classical traditional Chinese formulation, has attracted more and more attention. This study was carried out to analyze the constituents of EZW absorbed into blood and find out the potential active ingredients for treating osteoporosis (OP) with kidney-yin deficiency (KYD). The rat model of OP with KYD was achieved by ovariectomies and using the mixture of thyroxine and reserpine. Then ultra-high performance liquid chromatography coupled with a quadrupole time-of-flight mass spectrometer (UPLC-Q/TOF-MS) combined with statistical analysis was used to analyze the constituents of EZW absorbed into blood and differential components between the normal and OP with KYD rats. Finally, the components identified in OP with KYD rats were docked with targets of OP with KYD found in online databases. The results of molecular docking were adopted to find the potential active ingredients and further verified in vitro experiment. A total of 21 prototype compounds and 69 metabolites were identified in serum. Among them, 63 components in model rats and 50 components in normal rats were summarized, respectively. Most of the identified metabolites in serum of model rats were produced by hydrolysis, oxidation or glucuronidation, while in serum of normal rats were produced by hydrolysis, oxidation and methylation. According to the results of molecular docking, specnuezhenide, salidroside, tyrosol, echinacoside and verbascoside could be classified as potential active ingredients. The activity of salidroside and a metabolite was verified by pharmacodynamics analysis. In summary, UPLC-Q/TOF-MS system was combined with molecular docking to search the potential active ingredients from model rats of OP with KYD, which provided a new idea for the research on the pharmacodynamic material basis of other traditional medicine. Moreover, the result of this study lays the foundation for further study regarding the mechanism of EZW in treating OP with KYD.

Visualization of the distribution of anthraquinone components from madder roots in rat kidneys by desorption electrospray ionization-time-of-flight mass spectrometry imaging.

Madder color (MC), a natural dye isolated from Rubia tinctorum, is a potent carcinogen that targets the outer stripe of outer medulla (OSOM) in the kidneys of rats. To clarify the role of MC components in renal carcinogenesis, we examined distributions of MC components and metabolites in the kidneys of rats treated with MC using desorption electrospray ionization-mass spectrometry imaging (DESI-MSI). Alizarin, lucidin, munjistin, nordamnacanthal, purpurin, pseudopurpurin, rubiadin, and some other metabolites detected and identified by liquid chromatography time-of-flight MS analysis of rat serum 1 h after MC administration were subjected to DESI-MSI. This analysis enabled visualization of the distribution of anthraquinones in the kidney, and the ion images showed a characteristic distribution according to their chemical structure. Among the components, lucidin and rubiadin specifically localized in the OSOM, suggesting that their genotoxicity was a direct cause of MC carcinogenesis. Alizarin showed greater distribution in the OSOM than the cortex and may therefore participate in renal carcinogenicity owing to its tumor-promoting activity. Overall, our data suggested that the distribution of carcinogenic components to the OSOM was responsible for the site-specific renal carcinogenicity of MC and that DESI-MSI analysis may be a powerful tool for exploring the mechanisms of chemical carcinogenesis.

Dissection of the potential anti-diabetes mechanism of salvianolic acid B by metabolite profiling and network pharmacology.

RATIONALE: Salvianolic acid B (Sal B), the Q-marker in Salvia miltiorrhiza, was proved to present an obvious anti-diabetes effect when treated as a food intake. Until now, the metabolism feature, tissue distribution and anti-diabetes mechanism of Sal B have not been fully elucidated. METHODS: The metabolites of Sal B in rats were profiled using ultrahigh-performance liquid chromatography coupled with time-of-flight mass spectrometry. The potential anti-diabetes mechanism of Sal B was predicted by network pharmacology. RESULTS: A total of 31 metabolites were characterized in rats after ingestion of Sal B at a dosage of 40 mg/kg, including 1 in plasma, 19 in urine, 31 in feces, 0 in heart, 0 in liver, 0 in spleen, 1 in lung, 1 in kidney and 0 in brain. Among them, 18 metabolites were reported for the first time. Phase I reactions of hydrolysis, hydrogenation, dehydroxylation, hydroxylation, decarboxylation and isomerization, and phase II reactions of methylation were found in Sal B. Notably, decarboxylation and dehydroxylation were revealed in Sal B for the first time. The pharmacology network results showed that Sal B and its metabolites could regulate ALB, PLG, ACE, CASP3, MMP9, MMP2, MTOR, etc. The above targets were involved in insulin signaling pathway, PI3K-Akt signaling pathway, HIF-1 signaling pathway, TNF signaling pathway, etc. CONCLUSIONS: The metabolism feature of Sal B in vivo was systematically revealed, and its anti-diabetes mechanism for further pharmacological validations was predicted based on metabolite profiling and network pharmacology for the first time.

Chemicalome and metabolome profiling of Chai-Gui Decoction using an integrated strategy based on UHPLC-Q-TOF-MS/MS analysis.

Traditional Chinese medicine prescriptions are widely believed to exert therapeutic benefits via a multiple-component and multiple-target mode. The systemic profiling of their in vitro chemicalome and in vivo metabolome is of great importance for further understanding their clinical value. Herein, an integrated strategy using ultra-performance liquid chromatography coupled with quadruple time-of-flight mass spectrometry was proposed to profile the chemicalome and metabolome of Chai-Gui Decoction. Particularly, an approach combined mass defect filter, characteristic product ion filter, and neutral loss filter was adopted to identify metabolites in plasma, urine, bile, and feces by MetabolitePilot. Consequently, a total of 174 constituents were identified or tentatively characterized and 70 metabolites that related to 21 representative structural components were matched in rat biofluids. Among them, 19 prototypes and 7 metabolites that contributed to flavonoids, monoterpenes, and phenylpropanoids were detected distribution in brain, heart, kidney, liver, lung or spleen. This study provided a generally applicable approach to comprehensive investigation on chemicalome and metabolome of traditional Chinese medicine prescriptions, and offered reasonable guidelines for further screening of quality control indicators of Chai-Gui Decoction.

Molecular Mapping of Neutral Lipids Using Silicon Nanopost Arrays and TIMS Imaging Mass Spectrometry.

We demonstrate the utility of combining silicon nanopost arrays (NAPA) and trapped ion mobility imaging mass spectrometry (TIMS IMS) for high spatial resolution and specificity mapping of neutral lipid classes in tissue. Ionization of neutral lipid species such as triglycerides (TGs), cholestryl esters (CEs), and hexosylceramides (HexCers) from biological tissues has remained a challenge for imaging applications. NAPA, a matrix-free laser desorption ionization substrate, provides enhanced ionization efficiency for the above-mentioned neutral lipid species, providing complementary lipid coverage to matrix-assisted laser desorption ionization (MALDI). The combination of NAPA and TIMS IMS enables imaging of neutral lipid species at 20 µm spatial resolution while also increasing molecular coverage greater than 2-fold using gas-phase ion mobility separations. This is a significant improvement with respect to sensitivity, specificity, and spatial resolution compared to previously reported imaging studies using NAPA alone. Improved specificity for neutral lipid analysis using TIMS IMS was shown using rat kidney tissue to separate TGs, CEs, HexCers, and phospholipids into distinct ion mobility trendlines. Further, this technology allowed for the separation of isomeric species, including mobility resolved isomers of Cer(d42:2) (m/z 686.585) with distinct spatial localizations measured in rat kidney tissue section.

Antiurolithic effects of medicinal plants: results of in vivo studies in rat models of calcium oxalate nephrolithiasis-a systematic review.

Urolithiasis is one of the oldest diseases affecting humans, while plants are one of our oldest companions providing food, shelter, and medicine. In spite of substantial progress in understanding the pathophysiological mechanisms, treatment options are still limited, often expensive for common people in most parts of the world. As a result, there is a great interest in herbal remedies for the treatment of urinary stone disease as an alternative or adjunct therapy. Numerous in vivo and in vitro studies have been carried out to understand the efficacy of herbs in reducing stone formation. We adopted PRISMA guidelines and systematically reviewed PubMed/Medline for the literature, reporting results of various herbal products on in vivo models of nephrolithiasis/urolithiasis. The Medical Subject Heading Terms (Mesh term) "Urolithiasis" was used with Boolean operator "AND" and other related Mesh Unique terms to search all the available records (July 2019). A total of 163 original articles on in vivo experiments were retrieved from PubMed indexed with the (MeshTerm) "Urolithiasis" AND "Complementary Therapies/Alternative Medicine, "Urolithiasis" AND "Plant Extracts" and "Urolithiasis" AND "Traditional Medicine". Most of the studies used ethylene glycol (EG) to induce hyperoxaluria and nephrolithiasis in rats. A variety of extraction methods including aqueous, alcoholic, hydro-alcoholic of various plant parts ranging from root bark to fruits and seeds, or a combination thereof, were utilized. All the investigations did not study all aspects of nephrolithiasis making it difficult to compare the efficacy of various treatments. Changes in the lithogenic factors and a reduction in calcium oxalate (CaOx) crystal deposition in the kidneys were, however, considered favorable outcomes of the various treatments. Less than 10% of the studies examined antioxidant and diuretic activities of the herbal treatments and concluded that their antiurolithic activities were a result of antioxidant, anti-inflammatory, and/or diuretic effects of the treatments.

Diet-induced oxalate nephropathy from excessive nut and seed consumption.

Oxalate is a metabolite consumed in nuts, beans and leaves, and excreted in urine. Oxalosis can cause nephropathy. We describe a rare case of a high-oxalate diet intended for irritable bowel syndrome (IBS) treatment causing oxalate nephropathy. A 59-year-old woman with a history of controlled hypertension presented with creatinine 1.8 mg/dL, increased from baseline 1.3 mg/dL. She denied recent illness, urinary stones, medication adjustments, herbal supplements and non-steroidal anti-inflammatory drugs use. Diet included six tablespoons of chia seeds and five handfuls of almonds daily to manage IBS symptoms. Her electrolytes, urinalysis and renal ultrasound were unremarkable. Her 24-hour urine output revealed increased oxalate and low citrate. Renal biopsy showed glomerulosclerosis, fibrosis and calcium oxalate deposition. She switched to a low-oxalate diet, with improvement in laboratory markers. An earlier dietary history could have raised concern for oxalosis prior to renal biopsy. Providers should be trained to identify at-risk patients and provide appropriate dietary counselling.

Effect of occupational exposure to petrol and gasoline components on liver and renal biochemical parameters among gas station attendants, a review and meta-analysis.

OBJECTIVES: Kidney and liver are of the most affected organs during permanent exposure to petrol and gasoline components in gas stations. This study aims to investigate the renal and liver involvements in these workers using meta-analysis. METHODS: PubMed, Scopus, Science direct, ISI web of science, and Google scholar motor engine were searched using Mesh terms of the relevant keywords. Screening of titles, abstracts and full texts was continued until the eligible articles meeting the inclusion/exclusion criteria were selected. Quality assessment was conducted using NOS (Newcastle-Ottawa Quality score). The pooled standard mean difference of the renal and liver indices between exposed/unexposed groups was estimated using Stata ver. 11 software. RESULTS: In this systematic review, 22 papers were entered. The pooled standard mean difference (95% confidence interval) between exposed and unexposed groups was estimated as of 0.74 (0.28, 1.21) for alkaline phosphatase (ALP), 2.44 (1.80, 3.08) for aspartate transaminase (AST), 2.06 (1.42, 2.69) for alanine transaminase (ALT), 0.10 (-0.09, 0.29) for total Bilirubin (TB), 0.74 (-0.42, -1.90) for total protein (TP), -0.49 (-0.82, -0.15) for albumin, 0.88 (-0.10, 1.87) for uric acid, 1.02 (0.45, 1.59) for creatinine and 1.44 (0.75, 2.13) for blood urea nitrogen (BUN). CONCLUSION: Our meta-analysis showed that the serum AST, ALT, ALP, total protein, total bilirubin, BUN, uric acid and creatinine levels were higher among workers exposed to petrol and gasoline than control group, while albumin was lower in the serum of the exposed workers. Therefore, occupational exposure to gasoline stations can create adverse effects on kidney and liver function.

Synthesis and comparative assessment of antiradical activity, toxicity, and biodistribution of κ-carrageenan-capped selenium nanoparticles of different size: in vivo and in vitro study.

In the present study, water-soluble hybrid selenium-containing nanocomposites have been synthesised via soft oxidation of selenide-anions, preliminarily generated from elemental bulk-selenium in the base-reduction system 'N2H4-NaOH'. The nanocomposites obtained consist of Se0NPs (4.6-24.5 nm) stabilised by κ-carrageenan biocompatible polysaccharide. The structure of these composite nanomaterials has been proven using complementary physical-chemical methods: X-ray diffraction analysis, transmission electron microscopy, optical spectroscopy, and dynamic light scattering. Optical ranges of 'emission/excitation' of aqueous solutions of nanocomposites with Se0NPs of different sizes are established and the most important parameters of their luminescence are determined. For the obtained nanocomposites, the expressed antiradical activity against free radicals 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid has been found, the value of which depends on the size of selenium nanoparticles. It is experimentally revealed that all obtained nanocomposites are low toxic (LD50 >2000 mg/kg). It is also found that small selenium nanoparticles (6.8 nm), in contrast to larger nanoparticles (24.5 nm), are accumulated in organisms to significantly increase the level of selenium in the liver, kidneys, and brain (in lesser amounts) of rats.

Chronic pancreatitis in farmed pigs fed excessive zinc oxide.

Most of the pigs on a farm in Aichi Prefecture, Japan had chronic diarrhea and severe wasting. The pigs had consumed 8,000 ppm zinc oxide (ZnO) as a feed additive. The pancreas of each of 4 autopsied pigs was less than half the normal size. Acinar cells were considerably decreased. Epithelial duct-like cells were increased and tested positive for cytokeratin AE1/AE3, Ki67, PGP9.5, and Sox9. Pancreatic islet cells were decreased and shrunken. The α and δ cells were relatively decreased, and their distribution was abnormal. Islet cells were positive for PGP9.5. The livers and kidneys had high accumulations of zinc (Zn; 788 µg/g and 613 µg/g, respectively). Copper was deficient in the liver, likely as a result of Zn poisoning. Our immunohistologic examination suggested that the high dose of ZnO could influence the function of islet cells in addition to that of acinar cells. Given that colistin sulfate has been banned as a feed additive in order to reduce antimicrobial use in Japan, the use of ZnO in the livestock industry is expected to increase. Zn supplementation of pig feed must be monitored to prevent Zn poisoning and contamination of soil and water.

Fortifying diet with rapeseed oil instead of butterfat attenuates the progression of diet-induced non-alcoholic fatty liver disease (NAFLD) and impairment of glucose tolerance.

BACKGROUND: Absolute dietary fat intake but even more so fatty acid pattern is discussed to be critical in the development of non-alcoholic fatty liver disease (NAFLD). Here, we determined if switching a butterfat enriched diet to a rapeseed oil (RO) enriched diet affects progression of an existing NAFLD and glucose intolerance in mice. METHODS: For eight weeks, female C57Bl/6J mice were either fed a liquid control (C) or a butterfat-, fructose- and cholesterol-rich diet (BFC, 25E% butterfat) to induce early signs of steatohepatitis and glucose intolerance in mice. For additional five weeks mice received either BFC or C or a fat-, fructose- and cholesterol-rich and control diet, in which butterfat was replaced with RO (ROFC and CRO). Markers of glucose metabolism, liver damage and intestinal barrier were assessed. RESULTS: Exchanging butterfat with RO attenuated the progression of BFC diet-induced NAFLD and glucose intolerance. Beneficial effects of RO were associated with lower portal endotoxin levels and an attenuation of the induction of the toll-like receptor-4-dependent signaling cascades in liver. Peroxisome proliferator-activated receptor γ activity was induced in small intestine of ROFC-fed mice. CONCLUSION: Taken together, exchanging butterfat with RO attenuated the progression of diet-induced steatohepatitis and glucose intolerance in mice.

Minimizing Visceral Fat Delocalization on Tissue Sections with Porous Aluminum Oxide Slides for Imaging Mass Spectrometry.

A high correlation of bioanalytes with their corresponding histologies is the landmark feature of matrix-assisted laser desorption ionization (MALDI) imaging mass spectrometry (IMS). Lipids are one of the most studied classes of biomolecules, and monitoring lipid distribution and abundance in tissue samples can lead to major inputs in the understanding of disease. Lipid delocalization and ion suppression are two major effects that can lead to misinterpretation of the IMS results to an unaware analyst. We and others have observed that tissue specimens containing high amounts of visceral fat are challenging to analyze because of fat delocalization on and off section leading to significant triacylglyceride and phospholipid delocalization and major ion suppression effects. In this work, we introduce a novel and easy to produce reusable porous aluminum oxide sample slide that minimizes visceral fat delocalization after thaw-mounting of tissue sections. Using fatty mouse kidneys and other tissues, we demonstrate its efficacy in minimizing delocalization of triacylglycerides, the primary constituents of fat, and the resulting beneficial effects on phospholipid MALDI IMS.

Elevated Arsenic and Lead Concentrations in Natural Healing Clay Applied Topically as a Treatment for Ulcerative Dermatitis in Mice.

Ulcerative dermatitis in laboratory mice remains an ongoing clinical problem and animal welfare issue. Many products have been used to treat dermatitis in mice, with varying success. Recently, the topical administration of healing clays, such as bentonite and green clays, has been explored as a viable, natural treatment. We found high concentrations of arsenic and lead in experimental samples of therapeutic clay. Given the known toxic effects of these environmental heavy metals, we sought to determine whether the topical administration of a clay product containing bioavailable arsenic and lead exerted a biologic effect in mice that potentially could introduce unwanted research variability. Two cohorts of 20 singly housed, shaved, dermatitis free, adult male CD1 mice were dosed daily for 2 wk by topical application of saline or green clay paste. Samples of liver, kidney and whole blood were collected and analyzed for total arsenic and lead concentrations. Hepatic and renal concentrations of arsenic were not different between treated and control mice in either cohort; however, hepatic and renal concentrations of lead were elevated in clay treated mice compared to controls in both cohorts. In addition, in both cohorts, the activity of δ-aminolevulinate acid dehydratase, an enzyme involved with heme biosynthesis and a marker of lead toxicity, did not differ significantly between the clay-treated mice and controls. We have demonstrated that these clay products contain high concentrations of arsenic and lead and that topical application can result in the accumulation of lead in the liver and kidneys; however, these concentrations did not result in measurable biologic effects. These products should be used with caution, especially in studies of lead toxicity, heme biosynthesis, and renal α2 microglobulin function.

Proteomic analysis of rat kidney under maleic acid treatment by SWATH-MS technology.

RATIONALE: Maleic acid is an industrial-grade chemical that is often used in adhesives, stabilizers, and preservatives. It is unknown whether long-term consumption of maleic acid modified starch is harmful to humans. However, many studies have indicated that maleic acid causes renal tubular damage in animal models, even as the associated pathways remain unclear. Sequential window acquisition of all theoretical fragment ion spectra (SWATH) is the most innovative of the label-free quantitative technologies which have better quantification performance. Therefore, SWATH technology was used to investigate the effect of maleic acid on the rat kidney proteome in this study. METHODS: Sprague-Dawley(SD) rats were treated with 0 mg/kg (control), 6 mg/kg (low-dose), 10 mg/kg (medium-dose), and 60 mg/kg (high-dose) of maleic acid. After kidney protein extraction, 28% SDS-PAGE was used, followed by in-gel digestion and desalting. Next, the samples were analyzed with ultra-performance liquid chromatography (UPLC) coupled with quadrupole time-of-flight mass spectrometry (Q-TOF MS), and data-dependent acquisition (DDA) and SWATH technology were also used. The gene ontology and pathway analysis were accomplished. Ultimately, these protein biomarkers were validated by using scheduled high-resolution multiple reaction monitoring (sMRMHR ). RESULTS: Comparisons of the control group with the other three groups revealed that 95, 130, and 103 proteins were expressed at significantly different levels in the control group and in the low-dose, medium-dose, and high-dose groups, respectively. According to the gene ontology analysis, the major processes that these proteins were involved in were metabolic processes, biological regulation, cellular processes, and responses to stimuli; the major functions that these proteins were involved in were binding, hydrolase activity, catalytic activity, and oxidoreductase activity; and the major cellular components hat they were involved in were the cytoplasm, extracellular region, membrane, and mitochondria. According to the KEGG pathway analysis, these proteins were involved in 35 pathways, five of which, the carbohydrate metabolism, folate biosynthesis, renal tubular resorption, amino acid metabolism, and Ras signaling pathways, are discussed in this study. Ultimately, 19 proteins involved in 12 important pathways were validated by sMRMHR . CONCLUSIONS: It was demonstrated that maleic acid caused insufficient energy production, which might lead to a decrease in the activity of the sodium-potassium ATP pump and hydrogen ion ATP pump, which could in turn have caused renal tubular resorption and hydrogen ion regulation to be blocked, thus leading to the accumulation of hydrogen ions in the renal tubules, which would then result in renal tubular acidification followed finally by Fanconi syndrome.