Proliferative and nonproliferative lesions of the rat and mouse urinary system

GPER expression prevents estrogen-induced urinary retention in obese mice

Long-term administration of exogenous estrogen is known to cause urinary retention and marked, often fatal, bladder distention in both male and female mice. Estrogen-treated mice have increased bladder pressure and decreased urine flow, suggesting that urinary retention in estrogen-treated mice is due to infravesicular obstruction to urine outflow. Thus, the condition is commonly referred to as bladder outlet obstruction (BOO). Obesity can also lead to urinary retention. As the effects of estrogen are mediated by multiple receptors, including estrogen receptors ERα and ERβ and the G protein-coupled estrogen receptor (GPER), we sought to determine whether GPER plays a role in estrogen-induced BOO, particularly in the context of obesity. Wild type and GPER knockout (KO) mice fed a high-fat diet were ovariectomized or left ovary-intact (sham surgery) and supplemented with slow-release estrogen or vehicle-only pellets. Supplementing both GPER KO and wild type obese mice with estrogen for 8 weeks resulted in weight loss, splenic enlargement, and thymic atrophy, as expected. However, estrogen-treated obese GPER KO mice developed abdominal distension, debilitation, and ulceration of the skin surrounding the urogenital opening. At necropsy, these mice had prominently distended bladders and hydronephrosis. In contrast, estrogen-treated obese wild type mice only rarely displayed these signs. Our results suggest that, under conditions of obesity, estrogen induces BOO as a result of ERα-driven pathways and that GPER expression is protective against BOO.

Survival impact of [225Ac]Ac-DOTATOC alpha-therapy in a preclinical model of pancreatic neuroendocrine tumor liver micrometastases

Although peptide radionuclide therapy (PRRT) using a somatostatin analog (SSA) radiolabeled with a beta- emitter: [177Lu]Lu-DOTATATE has shown a good clinical efficacy in neuroendocrine tumors (NETs), most of the patients only achieved tumoral stabilization and rare but severe long-term hematological toxicities have been reported. One of the promising options to improve PRRT is targeted alpha therapy. It is therefore essential to propose animal models that can mimic systemic spread disease, especially microscopic disease such as early stage of NET liver metastases to explore targeted alpha therapy. Herein, we report the evaluation of efficacy and toxicity of [225Ac]Ac-DOTATOC in an original preclinical murine model simulating the development of well-characterized liver metastases of pancreatic NETs with SSTR overexpression.

METHODS

A mouse model of liver metastases of pancreatic NETs was developed by intraportal injection of AR42J cells and explored using [68 Ga]Ga-DOTATOC and [18F]F-FDG PET/MRI. Biodistribution study and radiation dosimetry of [225Ac]Ac-DOTATOC were determined in subcutaneous tumor-bearing NMRI-nude mice. Efficacy and toxicity were determined by intravenous injection of increasing activities of [225Ac]Ac-DOTATOC 10 days after intraportal graft.

RESULTS

Liver tumors showed a high uptake of [68 Ga]Ga-DOTATOC and no uptake of [18F]F-FDG confirming the well-differentiated phenotype. All groups treated with [225Ac]Ac-DOTATOC showed a significant increase in overall survival compared with DOTATOC-treated mice, especially those treated with the highest activities: 53 days with 240 kBq (p = 0.0001), and 58 days with 2 × 120 kBq (p < 0.0001) vs 28 days with non-radiolabeled DOTATOC. On blood tests, a transient and moderate decreased in white blood cells count after treatment and no severe hepatic or renal toxicity were observed after treatment which was consistent with pathological and radiation dosimetry findings.

CONCLUSION

[225Ac]Ac-DOTATOC exhibit a favorable efficacy and toxicity profile in a mouse model of liver micrometastatic pancreatic NET.

Preclinical evaluation of [18F]SYN1 and [18F]SYN2, novel radiotracers for PET myocardial perfusion imaging

BACKGROUND

Positron emission tomography (PET) is now an established diagnostic method for myocardial perfusion imaging (MPI) in coronary artery disease, which is the main cause of death globally. The available tracers show several limitations, therefore, the 18F-labelled tracer is in high demand nowadays. The preclinical studies on normal Wistar rats aimed to characterise two potential, novel radiotracers, [18F]SYN1 and [18F]SYN2, to evaluate which is a better candidate for PET MPI cardiotracer.

RESULTS

The dynamic microPET images showed rapid myocardial uptake for both tracers. However, the uptake was higher and also stable for [18F]SYN2, with an average standardized uptake value of 3.8. The biodistribution studies confirmed that [18F]SYN2 uptake in the cardiac muscle was high and stable (3.02%ID/g at 15 min and 2.79%ID/g at 6 h) compared to [18F]SYN1 (1.84%ID/g at 15 min and 0.32%ID/g at 6 h). The critical organs determined in dosimetry studies were the small intestine and the kidneys. The estimated effective dose for humans was 0.00714 mSv/MBq for [18F]SYN1 and 0.0109 mSv/MBq for [18F]SYN2. The tested dose level of 2 mg/kg was considered to be the No Observed Adverse Effect Level (NOAEL) for both candidates. The better results were achieved for [18F]SYN2, therefore, further preclinical studies were conducted only for this tracer. Radioligand binding assays showed significant responses in 3 from 68 assays: muscarinic acetylcholine M1 and M2 receptors and potassium channel hERG. The compound was mostly metabolised via an oxidative N-dealkylation, while the fluor substituent was not separated from the molecule.

CONCLUSION

[18F]SYN2 showed a favourable pharmacodynamic and pharmacokinetic profile, which enabled a clear visualization of the heart in microPET. The compound was well-tolerated in studies in normal rats with moderate radiation exposure. The results encourage further exploration of [18F]SYN2 in clinical studies.

A 90-day preclinical toxicological evaluation in rats of a highly purified and concentrated mulberry leaf extract

Mulberry (genus Morus) leaves have long been used as a human food, especially in Asia, and animal feed. More recently, mulberry leaf extracts have been introduced as a convenient way to consume mulberry for non-nutritional functional effects. Reducose® 5% is an Morus alba leaf extract that has been highly purified and standardized to a content of 5 ± 0.5% 1-deoxynojirimycin, a naturally present polyhydroxylated piperidine alkaloid analog of D-glucose. This extract has previously been evaluated in acute and subacute (28-day) oral toxicity studies in which no adverse effects of the test item were observed in mice or rats, respectively. Due to continued and growing interest in the extract in multinational markets, we have now further investigated potential toxic effects in subchronic (90-day) oral toxicity study in male and female Han:WIST rats. The test item was administered at doses of 850, 1700, and 2550 mg/kg bw/day, and did not cause adverse effects in clinical signs, body weight development, clinical pathology, gross pathology, or histopathology in comparison to the vehicle-control group. The no-observed-adverse-effect-level was determined to be 2550 mg/kg bw/day. These results add to the existing body of both preclinical and clinical work relevant to the safety of the extract and of interest to regulators in various global markets.

Oral sub-chronic toxicity of fingerroot (Boesenbergia rotunda) rhizome extract formulation in Wistar rats

Background

Boesenbergia rotunda (fingerroot) rhizome extract contains two major bioactive components, panduratin A and pinostrobin. In our previous study, we found the anti-inflammatory effects of the fingerroot extract against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in golden Syrian hamsters. In the present study, we evaluated the sub-chronic toxicity of a fingerroot extract formulation over 90 consecutive days of oral administration.

Methods

We enhanced the water solubility of a fingerroot extract by formulating it with cyclodextrin, containing panduratin A (29% w/w) and pinostrobin (32% w/w). This formulation was administered to male and female Wistar rats at doses of 25, 50, or 100 mg/kg/day for a duration of 90 days. Additionally, two recovery groups, comprising a control group and a high-dose group, were designated for a 14-day observation period to assess the persistence and reversibility of potential adverse effects. Throughout the experiment, we performed clinical and health observations, followed by hematological testing, clinical biochemistry analysis, necropsy examination, and histopathological evaluation at the end of the experiment.

Results

The administration of the fingerroot extract formulation at doses of 25, 50, or 100 mg/kg/day did not result in mortality or clinical signs of toxicity. No clinically significant findings were associated with the oral administration of the fingerroot extract formulation.

Conclusion

The fingerroot extract formulation showed no serious adverse effects at doses up to 100 mg/kg/day in Wistar rats under the experimental condition. Consequently, the No Observed Adverse Effect Level (NOAEL) was considered to be 100 mg/kg/day. This finding contributes significance for future developments involving fingerroot extract in herbal medicinal products targeting chronic inflammation.

CD44 expression in renal tubular epithelial cells in the kidneys of rats with cyclosporine-induced chronic kidney disease

Renal tubular epithelial cell (TEC) injury is the most common cause of drug-induced kidney injury (DIKI). Although TEC regeneration facilitates renal function and structural recovery following DIKI, maladaptive repair of TECs leads to irreversible fibrosis, resulting in chronic kidney disease (CKD). CD44 is specifically expressed in TECs during maladaptive repair in several types of rat CKD models. In this study, we investigated CD44 expression and its role in renal fibrogenesis in a cyclosporine (CyA) rat model of CKD. Seven-week-old male Sprague-Dawley rats fed a low-salt diet were subcutaneously administered CyA (0, 15, or 30 mg/kg) for 28 days. CD44 was expressed in atrophic, dilated, and hypertrophic TECs in the fibrotic lesions of the CyA groups. These TECs were collected by laser microdissection and evaluated by microarray analysis. Gene ontology analysis suggested that these TECs have a mesenchymal phenotype, and pathway analysis identified CD44 as an upstream regulator of fibrosis-related genes, including fibronectin 1 (Fn1). Immunohistochemistry revealed that epithelial and mesenchymal markers of TECs of fibrotic lesions were downregulated and upregulated, respectively, and that these TECs were surrounded by a thickened basement membrane. In situ hybridization revealed an increase in Fn1 mRNA in the cytoplasm of TECs of fibrotic lesions, whereas fibronectin protein was localized in the stroma surrounding these tubules. Enzyme-linked immunosorbent assay revealed increased serum CD44 levels in CyA-treated rats. Collectively, these findings suggest that CD44 contributes to renal fibrosis by inducing fibronectin secretion in TECs exhibiting partial epithelial-mesenchymal transition and highlight the potential of CD44 as a biomarker of renal fibrosis.

Safety assessment of a proprietary fermented soybean solution, Symbiota®, as an ingredient for use in foods and dietary supplements: Non-clinical studies and a randomized trial

A safety evaluation was performed of Symbiota®, which is made by a proprietary anaerobic fermentation process of soybean with multistrains of probiotics and a yeast. The battery of genotoxicity studies showed that Symbiota® has no genotoxic effects. Safety and tolerability were further assessed by acute or repeated dose 28- and 90-day rodent studies, and no alterations in clinical observations, ophthalmological examination, blood chemistry, urinalysis, or hematology were observed between the control group and the different dosing groups (1.5, 5, and 15 mL/kg/day). There were no adverse effects on specific tissues or organs in terms of weight and histopathology. Importantly, the Symbiota® treatment did not perturb hormones and other endocrine-related endpoints. Of note, the No-Observed-Adverse-Effect-Level was determined to be 15 mL/kg/day in rats. Moreover, a randomized, double-blind, placebo-controlled clinical trial was recently conducted with healthy volunteers who consumed 8 mL/day of placebo or Symbiota® for 8 weeks. Only mild adverse events were reported in both groups, and the blood chemistry and blood cell profiles were also similar between the two groups. In summary, this study concluded that the oral consumption of Symbiota® at 8 mL/day by the general population does not pose any human health concerns.

Water-soluble phenolics from Phoenix dactylifera fruits as potential reno-protective agent against cisplatin-induced toxicity: pre- and post-treatment strategies

Nephrotoxicity is the major side effect of cisplatin, an effective platinum-based chemotherapeutic drug that is applicable in the treatment of several solid-tissue cancers. Studies have indicated that certain water-soluble phenolics offer renal protection. Thus, this study investigates the role of pre and post-treatment of rats with water-soluble phenolics from Phoenix dactylifera (PdP) against nephrotoxicity induced by cisplatin. Rats were either orally pretreated or post-treated with 200 mg/kg body weight of PdP before or after exposure to a single therapeutic dose of cisplatin (5 mg/kg body weight) for 7 successive days intraperitoneally. The protective effects of PdP against Cisplatin-induced nephrotoxicity was based on the evaluation of various biochemical and redox biomarkers, together with histopathological examination of kidney tissues. The composition, structural features, and antioxidative influence of PdP were determined based on chromatographic, spectroscopic, and in vitro antioxidative models. Cisplatin single exposure led to a substantial increase in the tested renal function biomarkers (uric acid, creatinine, and urea levels), associated with an increase in malondialdehyde indicating lipid peroxidation and a significant decline (p < 0.05) in reduced glutathione (GSH) levels in the renal tissue when compared with the control group. A marked decline exists in the kidney antioxidant enzymes (catalase, SOD, and GPx). Nevertheless, treatment with PdP significantly suppressed the heightened renal function markers, lipid peroxidation, and oxidative stress. Spectroscopic analysis revealed significant medicinal phenolics, and in vitro tests demonstrated antioxidative properties. Taken together, results from this study indicate that pre- and/or post-treatment strategies of PdP could serve therapeutic purposes in cisplatin-induced renal damage.

Safety of ashitaba sap as a Novel food pursuant to Regulation (EU) 2015/2283

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on ashitaba sap as a novel food (NF) pursuant to Regulation (EU) 2015/2283. Ashitaba sap is collected from harvested stems of Angelica keiskei plants. The principal constituents of the sap with regard to the safety assessment are chalcones (1%-2.25%) and furanocoumarins (< 0.01%). The applicant proposed to use the NF in food supplements at a maximum dose of 780 mg per day. The target population is adults excluding pregnant and lactating women. Taking into consideration the composition of the NF and the proposed uses, the composition of the NF is not nutritionally disadvantageous. There are no concerns regarding genotoxicity of the NF. Based on a 90-day oral toxicity study performed with the product as intended to be placed on the market (30% ashitaba sap powder and 70% cyclodextrins), the Panel establishes a safe dose of 0.5 mg/kg body weight (bw) per day for the product as it is intended to be placed on the market. For the target population, i.e. adults, this safe dose corresponds to 35 mg per day of the product as it is intended to be placed on the market and 137 mg per day of the NF, which is lower than the use level proposed by the applicant. The Panel concludes that the NF is safe for the target population at intake levels up to 137 mg per day.

Toxicological evaluation of a fish oil concentrate containing Very Long Chain Fatty Acids

Very long chain fatty acids (VLCFA) have a chain length ≥24 carbons. Fish contain low levels of these fatty acids. A commercial oil called EPAX® Evolve 05 with an up-concentration of VLCFAs of approximately 10 times, has been developed as a dietary supplement by Epax Norway AS. A series of toxicological studies were performed using mice and rats to determine the safety and toxicity of repeat dosing with a gavage administered VLCFA formulation. The results suggest transient lipid accumulation in kidneys and liver. Lipid accumulation was seen with the test item and with the soya control but was not dose related. Liver and kidney lipid accumulation, whilst present in 14- day repeat dose study, was absent in a 90-day rat study. No treatment-effect was seen in urine analysis in any of the studies. No treatment-related effects were seen with a functional observation battery, ophthalmological examination, haematology, urine analysis, oestrus cycle, thyroid hormones, organ weight, or histopathology. In the 90-day study the liver enzymes ALP, AST and ALT were statistically significantly increased with test item but within control values. There were no associated histological findings in the liver suggesting there was no toxic effect and the normalisation of values for all liver enzymes in the recovery groups suggests an adaptive response rather than a prevailing toxic response. The no-observed-adverse-effect level (NOAEL) was determined as 1200 mg VLCFA/kg b.w./day.

Guide for Combining Primary Tumors for Statistical Analysis in Rodent Carcinogenicity Studies

The Tumor Combination Guide was created at the request of the U. S. Food and Drug Administration (FDA) by a Working Group of biopharmaceutical experts from international societies of toxicologic pathology, the Food and Drug Administration (FDA), and members of the Standard for Exchange of Nonclinical Data (SEND) initiative, to assist pharmacology/toxicology reviewers and biostatisticians in statistical analysis of nonclinical tumor data. The guide will also be useful to study and peer review pathologists in interpreting the tumor data. This guide provides a higher-level hierarchy of tumor types or categories correlating the tumor names from the International Harmonization of Nomenclature and Diagnostic Criteria (INHAND) publications with those available in the NEOPLASM controlled terminology (CT) code list in SEND. The version of CT used in a study should be referenced in the nonclinical study data reviewer's guide (SDRG) (section 3.1) of electronic submissions to the FDA. The tumor combination guide instructions and examples are in a tabular format to make informed decisions for combining tumor data for statistical analysis. The strategy for combining tumor types for statistical analysis is based on scientific criteria gleaned from the current scientific literature; as SEND and INHAND terminology and information evolve, this guide will be updated.

Evaluation of the Mechanisms Involved in the Development of Bladder Toxicity following Exposure to Occupational Bladder Cancer Causative Chemicals Using DNA Adductome Analysis

Occupational exposure to aromatic amines (AAs) is an important risk factor for urinary bladder cancer. This study aimed to evaluate the toxicity of AAs and analyze the carcinogenic mechanisms in rat bladder by comprehensive analysis of DNA adducts (DNA adductome). DNA was extracted from the bladder epithelia of rats treated with AAs, including acetoacet-o-toluidine (AAOT) and o-toluidine (OTD), and adductome analysis was performed. Principal component analysis-discriminant analysis revealed that OTD and AAOT observed in urinary bladder hyperplasia could be clearly separated from the controls and other AAs. After confirming the intensity of each adduct, four adducts were screened as having characteristics of the OTD/AAOT treatment. Comparing with the in-house DNA adduct database, three of four candidates were identified as oxidative DNA adducts, including 8-OH-dG, based on mass fragmentation together with high-resolution accurate mass (HRAM) spectrometry data. Therefore, findings suggested that oxidative stress may be involved in the toxicity of rat bladder epithelium exposed to AAs. Consequently, the administration of apocynin, an inhibitor of nicotinamide adenine dinucleotide phosphate oxidase, in six-week-old rats fed with 0.6% OTD in their diet resulted in simple hyperplastic lesions in the bladder that were suppressed by apocynin. The labeling indices of Ki67, γ-H2AX, and 8-OHdG were significantly decreased in an apocynin concentration-dependent manner. These findings indicate that oxidative stress may have contributed to the development of urinary cancer induced by OTD.

Potential Defence Mechanisms Triggered by Monosodium Glutamate Sub-Chronic Consumption in Two-Year-Old Wistar Rats

Monosodium glutamate (MSG) is the sodium salt of glutamic acid (GLA), used as a flavour enhancer. MSG is considered a controversial substance. It is incriminated in disturbing the antioxidant system, but also has beneficial effects, as GLA metabolism plays a crucial role in homeostasis. This study highlights which positive or negative aspects of MSG sub-chronic consumption are better reflected in subjects potentially affected by advanced age. Daily doses of MSG were administered to four groups of two-year-old Wistar rats for 90 days: (I) 185 mg/kg bw, (II) 1500 mg/kg bw, (III) 3000 mg/kg bw and (IV) 6000 mg/kg bw, compared to a MSG non-consumer group. Aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, direct and total bilirubin, total cholesterol, triglycerides, creatinine and urea levels were analysed; stomach, liver and kidney samples were subjected to histopathological analysis. Although, in most cases, there were no statistical differences, interesting aspects of the dose-effect relationship were observed. After MSG sub-chronic consumption, the positive aspects of GLA seem to be reflected better than the negative ones. The hormesis effect, with low-level reactive oxygen species' protective effects and GLA metabolism, may represent the hypothesis of a potential defence mechanism triggered by MSG sub-chronic consumption in ageing rats.

Localization of unlabeled bepirovirsen antisense oligonucleotide in murine tissues using in situ hybridization and CARS imaging

Current methods for detecting unlabeled antisense oligonucleotide (ASO) drugs rely on immunohistochemistry (IHC) and/or conjugated molecules, which lack sufficient sensitivity, specificity, and resolution to fully investigate their biodistribution. Our aim was to demonstrate the qualitative and quantitative distribution of unlabeled bepirovirsen, a clinical stage ASO, in livers and kidneys of dosed mice using novel staining and imaging technologies at subcellular resolution. ASOs were detected in formalin-fixed paraffin-embedded (FFPE) and frozen tissues using an automated chromogenic in situ hybridization (ISH) assay: miRNAscope. This was then combined with immunohistochemical detection of cell lineage markers. ASO distribution in hepatocytes versus nonparenchymal cell lineages was quantified using HALO AI image analysis. To complement this, hyperspectral coherent anti-Stokes Raman scattering (HS-CARS) imaging microscopy was used to specifically detect the unique cellular Raman spectral signatures following ASO treatment. Bepirovirsen was localized primarily in nonparenchymal liver cells and proximal renal tubules. Codetection of ASO with distinct cell lineage markers of liver and kidney populations aided target cell identity facilitating quantification. Positive liver signal was quantified using HALO AI, with 12.9% of the ASO localized to the hepatocytes and 87.1% in nonparenchymal cells. HS-CARS imaging specifically detected ASO fingerprints based on the unique vibrational signatures following unlabeled ASO treatment in a totally nonperturbative manner at subcellular resolution. Together, these novel detection and imaging modalities represent a significant increase in our ability to detect unlabeled ASOs in tissues, demonstrating improved levels of specificity and resolution. These methods help us understand their underlying mechanisms of action and ultimately improve the therapeutic potential of these important drugs for treating globally significant human diseases.

A novel therapeutic strategy for non-muscle invasive bladder cancer: OncoTherad® immunotherapy associated with platelet-rich plasma

Patients with non-muscle invasive bladder cancer (NMIBC) that are unresponsive to Bacillus Calmette-Guérin (BCG) have historically had limited treatment options. A new perspective is represented by OncoTherad® (MRB-CFI-1) immunotherapy, a nanostructured inorganic phosphate complex associated with glycosidic protein, developed by the University of Campinas in Brazil. Previous studies have shown that Platelet-Rich Plasma (PRP) also acts on immune activation and exerts antitumor effects. This study characterized the effects of the OncoTherad® associated with PRP in the treatment of NMIBC chemically induced in mice. When treated intravesically with PRP only, mice showed 28.6% of tumor progression inhibition rate; with OncoTherad® 85.7%; and with OncoTherad®+PRP 71.4%. Intravesical treatments led to distinct activation of Toll-like Receptors (TLRs) 2 and 4-mediated innate immune system in the interleukins (canonical) and interferons (non-canonical) signaling pathways. OncoTherad® isolated or associated with PRP upregulated TLR4 and its downstream cascade mediators as well as increased interleukins 6 (IL-6) and 1β (IL-1β), and interferon-γ (IFN-γ). In this way, the NMIBC microenvironment was modulated to a cytotoxic profile correlated with the IL-1β increase by stimulating immune pathways for IFN-γ production and consequent cytotoxic T lymphocytes (as CD8+ T-cells) activation and regulatory T-cells (Tregs) reduction. In addition, PRP did not trigger carcinogenic effects through the biomarkers evaluated. Considering the possibility of personalizing the treatment with the PRP use as well as the antitumor properties of OncoTherad®, we highlight this association as a potential new therapeutic strategy for NMIBC, mainly in cases of relapse and/or resistance to BCG.

Quantifying acute kidney injury in an Ischaemia-Reperfusion Injury mouse model using deep-learning-based semantic segmentation in histology

This study focuses on ischaemia-reperfusion injury (IRI) in kidneys, a cause of acute kidney injury (AKI) and end-stage kidney disease (ESKD). Traditional kidney damage assessment methods are semi-quantitative and subjective. This study aims to use a convolutional neural network (CNN) to segment murine kidney structures after IRI, quantify damage via CNN-generated pathological measurements, and compare this to conventional scoring. The CNN was able to accurately segment the different pathological classes, such as Intratubular casts and Tubular necrosis, with an F1 score of over 0.75. Some classes, such as Glomeruli and Proximal tubules, had even higher statistical values with F1 scores over 0.90. The scoring generated based on the segmentation approach statistically correlated with the semiquantitative assessment (Spearman's rank correlation coefficient=0.94). The heatmap approach localised the intratubular necrosis mainly in the outer stripe of the outer medulla, while the tubular casts were also present in more superficial or deeper portions of the cortex and medullary areas. This study presents a CNN model capable of segmenting multiple classes of interest, including acute IRI-specific pathological changes, in a whole mouse kidney section and can provide insights into the distribution of pathological classes within the whole mouse kidney section.

Assessment of the impact of glyphosate and 2,4-D herbicides on the kidney injury and transcriptome changes in obese mice fed a Western diet

The development of chronic kidney disease has been associated with comorbidities resulting from the consumption of Westernized dietary (WD) patterns, including obesity and other metabolic dysfunctions. Kidneys also have a crucial role in the metabolism and excretion of xenobiotics, including herbicides. There is limited knowledge regarding the simultaneous exposure to WD and glyphosate (glypho) and 2,4-D, the most used herbicides globally. Thus, this study examined whether exposure to glypho and/or 2,4-D, either individually or in mixed, could impact the early effects of WD intake on kidney histology and gene expression in a rodent model. Male C57BL6J mice were fed a WD containing 20% lard, 0.2% cholesterol, 20% sucrose, and high sugar solution with 23.1 and 18.9 g/L of D-fructose and D-glucose for six months. During this period, the mice also received glypho (0.05 or 5 mg/kg/day), 2,4-D (0.02 or 2 mg/kg/day), or a mixture of both (0.05 +0.02, 5 +2 mg/kg/day) via intragastric administration five times per week. The doses were within or below the established regulatory limits. While single or mixed exposures did not alter WD-induced obesity, tubular lipid vacuolation, or increased serum creatinine levels; the exposure to higher doses of the mixture (5 +2) reduced the mesangial matrix area and tubular cell proliferation, while increasing the density of F4/80 macrophages in the renal interstitium. In terms of transcriptomic analysis, the herbicide mixture altered the expression of 415 genes in the kidney, which were found to be associated with immune response processes, particularly those related to phagocyte activity. While discrete, findings indicate that herbicide mixtures, rather than single exposures, might induce minor deleterious effects on the kidneys of obese mice under WD intake.

The Protective Potential of Aronia melanocarpa L. Berry Extract against Cadmium-Induced Kidney Damage: A Study in an Animal Model of Human Environmental Exposure to This Toxic Element

The impact of cadmium (Cd) on the function and structure of the kidney and the potential protective effect of an extract from Aronia melanocarpa L. berries were investigated in a rat model of low- and moderate-level environmental exposure to this heavy metal (1 and 5 mg Cd/kg feed for up to 24 months). The sensitive biomarkers of Cd-induced damage to the kidney tubules (N-acetyl-β-D-glucosaminidase (NAG), alkaline phosphatase (ALP), β2-microglobulin (β2-MG), and kidney injury molecule-1 (KIM-1) in the urine), clinically relevant early markers of glomerular damage (albumin in the urine and creatinine clearance), and other markers of the general functional status of this organ (urea, uric acid, and total protein in the serum and/or urine) and Cd concentration in the urine, were evaluated. The morphological structure of the kidney and inflammatory markers (chemerin, macrophage inflammatory protein 1 alpha (MIP1a), and Bcl2-associated X protein (Bax)) were also estimated. Low-level and moderate exposure to Cd led to damage to the function and structure of the kidney tubules and glomeruli. The co-administration of A. melanocarpa berry extract significantly protected against the injurious impact of this toxic element. In conclusion, even low-level, long-term exposure to Cd poses a risk of kidney damage, whereas an intake of Aronia berry products may effectively protect from this outcome.

Safety evaluation of a food enzyme containing endo-polygalacturonase and pectin lyase activities from the non-genetically modified Aspergillus tubingensis strain NZYM-PE

The food enzyme with the declared activities endo-polygalacturonase ((1-4)-α-D-galacturonan glycanohydrolase; EC 3.2.1.15) and pectin lyase ((1-4)-6-O-methyl-α-D-galacturonan lyase; EC 4.2.2.10) is produced with the non-genetically modified Aspergillus tubingensis strain NZYM-PE by Novozymes A/S. It is intended to be used in four food manufacturing processes: fruit and vegetable processing for juice production, fruit and vegetable processing for products other than juices, refined olive oil production and wine and wine vinegar production. Since residual amounts of total organic solids (TOS) are removed during production, dietary exposure was not calculated for refined olive oil production. For the remaining three food processes, it was estimated to be up to 0.132 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not indicate a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level (NOAEL) of 1,430 mg TOS/kg bw per day, the highest dose tested, which when compared with the estimated dietary exposure, resulted in a margin of exposure above 10,833. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and 13 matches were found, including one food allergen (papaya). The Panel considered that, under the intended conditions of use, the risk of allergic reactions upon dietary exposure to this food enzyme cannot be excluded, in particular for individuals sensitised to papaya, but that the risk will not exceed that of consumption of papaya. In addition, oral allergy reactions cannot be excluded in pollen-sensitised individuals. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns, under the intended conditions of use.

Anti-Oxidant, Anti-Mutagenic Activity and Safety Evaluation of Antrocin

Antrocin is a novel compound isolated from Antrodia cinnamomea, and is classified as a sesquiterpene lactone. The therapeutic efficacy of antrocin has been studied, and it has shown an antiproliferative effect on various cancers. The aim of this study was to evaluate the anti-oxidant activity, potential genotoxicity, and oral toxicity of antrocin. Ames tests with five different strains of Salmonella typhimurium, chromosomal aberration tests in CHO-K1 cells, and micronucleus tests in ICR mice were conducted. The results of anti-oxidant capacity assays showed that antrocin has great anti-oxidant activity and is a moderately strong antimutagenic agent. In the results of the genotoxicity assays, antrocin did not show any mutagenic potential. In the 28-day oral toxicity test, Sprague Dawley rats were gavaged with 7.5 or 37.5 mg/kg of antrocin for 28 consecutive days. In addition, 7.5 mg/kg sorafenib, an anti-cancer drug, was used as a positive control for toxicity comparison. At the end of the study, antrocin did not produce any toxic effects according to hematology, serum chemistry, urine analysis, or histopathological examinations. According to the results of the genotoxicity and 28-day oral toxicity study, antrocin, at a dose of 37.5 mg/kg, did not cause adverse effects and can be a reference dose for therapeutic agents in humans.

A comparative multi-level toxicity assessment of carbon-based Gd-free dots and Gd-doped nanohybrids from coffee waste: hematology, biochemistry, histopathology and neurobiology study

Here, a comparative toxicity assessment of precursor carbon dots from coffee waste (cofCDs) obtained using green chemistry principles and Gd-doped nanohybrids (cofNHs) was performed using hematological, biochemical, histopathological assays in vivo (CD1 mice, intraperitoneal administration, 14 days), and neurochemical approach in vitro (rat cortex nerve terminals, synaptosomes). Serum biochemistry data revealed similar changes in cofCDs and cofNHs-treated groups, i.e. no changes in liver enzymes' activities and creatinine, but decreased urea and total protein values. Hematology data demonstrated increased lymphocytes and concomitantly decreased granulocytes in both groups, which could evidence inflammatory processes in the organism and was confirmed by liver histopathology; decreased red blood cell-associated parameters and platelet count, and increased mean platelet volume, which might indicate concerns with platelet maturation and was confirmed by spleen histopathology. So, relative safety of both cofCDs and cofNHs for kidney, liver and spleen was shown, whereas there were concerns about platelet maturation and erythropoiesis. In acute neurotoxicity study, cofCDs and cofNHs (0.01 mg/ml) did not affect the extracellular level of L-[14C]glutamate and [3H]GABA in nerve terminal preparations. Therefore, cofNHs demonstrated minimal changes in serum biochemistry and hematology assays, had no acute neurotoxicity signs, and can be considered as perspective biocompatible non-toxic theragnostic agent.

Comparative Analysis of Hypertensive Tubulopathy in Animal Models of Hypertension and Its Relevance to Human Pathology

Assessment of hypertensive tubulopathy for more than fifty animal models of hypertension in experimental pathology employs criteria that do not correspond to lesional descriptors for tubular lesions in clinical pathology. We provide a critical appraisal of experimental hypertension with the same approach used to estimate hypertensive renal tubulopathy in humans. Four models with different pathogenesis of hypertension were analyzed-chronic angiotensin (Ang) II-infused and renin-overexpressing (TTRhRen) mice, spontaneously hypertensive (SHR), and Goldblatt two-kidney one-clip (2K1C) rats. Mouse models, SHR, and the nonclipped kidney in 2K1C rats had no regular signs of hypertensive tubulopathy. Histopathology in animals was mild and limited to variations in the volume density of tubular lumen and epithelium, interstitial space, and interstitial collagen. Affected kidneys in animals demonstrated lesion values that are significantly different compared with healthy controls but correspond to mild damage if compared with hypertensive humans. The most substantial human-like hypertensive tubulopathy was detected in the clipped kidney of 2K1C rats. For the first time, our study demonstrated the regular presence of chronic progressive nephropathy (CPN) in relatively young mice and rats with induced hypertension. Because CPN may confound the assessment of rodent models of hypertension, proliferative markers should be used to verify nonhypertensive tubulopathy.

Evaluation of the 52-week chronic toxicity of a novel phthalate-free plasticizer, Eco-DEHCH (bis(2-ethylhexyl) cyclohexane-1,4-dicarboxylate), in Han Wistar rats

Phthalate esters (PEs) are the most widely used class of plasticizers. Several PEs, however, were found to have adverse effects on the health of animals. A new phthalate-free plasticizer, Eco-DEHCH (bis(2-ethylhexyl) cyclohexane-1,4-dicarboxylate), was recently developed as an ecofriendly replacement for phthalate plasticizers and to be less harmful to organisms. The present study evaluated the long-term toxicity of Eco-DEHCH in Wistar Han rats to explore adverse effects and predict hazardous potential to humans. Forty male and forty female Wistar Han rats were exposed to Eco-DEHCH in dietary feed for 52 weeks, and their hematologic, coagulation, and serum biochemical parameters were monitored. The rats were subjected to close clinical, ophthalmic, and histopathologic examinations and urinalysis throughout the consumption of Eco-DEHCH. The effects of this plasticizer on food consumption and organ weight were also determined. Chronic exposure to Eco-DEHCH was generally safe, although it also resulted in α_2u-globulin accumulation, a parameter with no human relevance. In conclusion, Eco-DEHCH can serve as a safe and promising alternative plasticizer.

Re-evaluation of the risks to public health related to the presence of bisphenol A (BPA) in foodstuffs

In 2015, EFSA established a temporary tolerable daily intake (t-TDI) for BPA of 4 μg/kg body weight (bw) per day. In 2016, the European Commission mandated EFSA to re-evaluate the risks to public health from the presence of BPA in foodstuffs and to establish a tolerable daily intake (TDI). For this re-evaluation, a pre-established protocol was used that had undergone public consultation. The CEP Panel concluded that it is Unlikely to Very Unlikely that BPA presents a genotoxic hazard through a direct mechanism. Taking into consideration the evidence from animal data and support from human observational studies, the immune system was identified as most sensitive to BPA exposure. An effect on Th17 cells in mice was identified as the critical effect; these cells are pivotal in cellular immune mechanisms and involved in the development of inflammatory conditions, including autoimmunity and lung inflammation. A reference point (RP) of 8.2 ng/kg bw per day, expressed as human equivalent dose, was identified for the critical effect. Uncertainty analysis assessed a probability of 57-73% that the lowest estimated Benchmark Dose (BMD) for other health effects was below the RP based on Th17 cells. In view of this, the CEP Panel judged that an additional uncertainty factor (UF) of 2 was needed for establishing the TDI. Applying an overall UF of 50 to the RP, a TDI of 0.2 ng BPA/kg bw per day was established. Comparison of this TDI with the dietary exposure estimates from the 2015 EFSA opinion showed that both the mean and the 95th percentile dietary exposures in all age groups exceeded the TDI by two to three orders of magnitude. Even considering the uncertainty in the exposure assessment, the exceedance being so large, the CEP Panel concluded that there is a health concern from dietary BPA exposure.

Cytoprotective remedies for ameliorating nephrotoxicity induced by renal oxidative stress

AIMS

Nephrotoxicity is the hallmark of anti-neoplastic drug metabolism that causes oxidative stress. External chemical agents and prescription drugs release copious amounts of free radicals originating from molecular oxidation and unless sustainably scavenged, they stimulate membrane lipid peroxidation and disruption of the host antioxidant mechanisms. This review aims to provide a comprehensive collection of potential cytoprotective remedies in surmounting the most difficult aspect of cancer therapy as well as preventing renal oxidative stress by other means.

MATERIALS AND METHODS

Over 400 published research and review articles spanning several decades were scrutinised to obtain the relevant data which is presented in 3 categories; sources, mechanisms, and mitigation of renal oxidative stress.

KEY-FINDINGS

Drug and chemical-induced nephrotoxicity commonly manifests as chronic or acute kidney disease, nephritis, nephrotic syndrome, and nephrosis. Renal replacement therapy requirements and mortalities from end-stage renal disease are set to rapidly increase in the next decade for which 43 different cytoprotective compounds which have the capability to suppress experimental nephrotoxicity are described.

SIGNIFICANCE

The renal system performs essential homeostatic functions that play a significant role in eliminating toxicants, and its accumulation and recurrence in nephric tissues results in tubular degeneration and subsequent renal impairment. Global statistics of the latest chronic kidney disease prevalence is 13.4 % while the end-stage kidney disease requiring renal replacement therapy is 4-7 million per annum. The remedial compounds discussed herein had proven efficacy against nephrotoxicity manifested consequent to impaired antioxidant mechanisms in preclinical models produced by renal oxidative stress activators.

Protective Effects of Omega-3 Supplementation against Doxorubicin-Induced Deleterious Effects on the Liver and Kidneys of Rats

Anthracycline doxorubicin (DOX) is still widely used as a chemotherapeutic drug for some solid tumors. Although DOX is highly effective, its side effects are limiting factors, such as cardio, nephro and hepatotoxicity. As such, approaches used to mitigate these adverse effects are highly encouraged. Omega 3 (ω-3), which is a class of long-chain polyunsaturated fatty acids, has been shown to have anti-inflammatory and antioxidant effects in preclinical bioassays. Thus, we evaluated the protective effects of ω-3 supplementation on hepatotoxicity and nephrotoxicity induced by multiple DOX administrations in rodents. Male Wistar rats (10 rats/group) were treated daily with ω-3 (400 mg/kg/day) by gavage for six weeks. Two weeks after the first ω-3 administration, the rats received DOX (3.5 mg/kg, intraperitoneal, 1×/week) for four weeks. DOX treatment reduced body weight gain increased systemic genotoxicity and caused liver-related (increase in serum ALT levels, thickness of the Glisson’s capsule, compensatory proliferation and p65 levels) and kidney-related (increase in serum urea and creatinine levels, and incidence of tubular dilatation) deleterious outcomes. In contrast, ω-3 supplementation was safe and abrogated the DOX-related enhancement of systemic genotoxicity, serum urea and creatinine levels. Furthermore, ω-3 intervention reduced by 50% the incidence of kidney histological lesions while reducing by 40–50% the p65 protein level, and the proliferative response in the liver induced by DOX. Our findings indicate that ω-3 intervention attenuated the DOX-induced deleterious effects in the liver and kidney. Therefore, our findings may inspire future mechanistical investigations and clinical interventions with ω-3 on the reported outcomes.

Renal toxicity and biokinetics models after repeated uranium instillation

During nuclear fuel processing, workers can potentially be exposed to repeated inhalations of uranium compounds. Uranium nephrotoxicity is well documented after acute uranium intake, but it is controversial after long-term or protracted exposure. This study aims to analyze the nephrotoxicity threshold after repeated uranium exposure through upper airways and to investigate the resulting uranium biokinetics in comparison to reference models. Mice (C57BL/6J) were exposed to uranyl nitrate (0.03-3 mg/kg/day) via intranasal instillation four times a week for two weeks. Concentrations of uranium in urines and tissues were measured at regular time points (from day 1 to 91 post-exposure). At each exposure level, the amount of uranium retained in organs/tissues (kidney, lung, bone, nasal compartment, carcass) and excreta (urine, feces) reflected the two consecutive weeks of instillation except for renal uranium retention for the highest uranium dose. Nephrotoxicity biomarkers, KIM-1, clusterin and osteopontin, are induced from day 4 to day 21 and associated with changes in renal function (arterial fluxes) measured using non-invasive functional imaging (Doppler-ultrasonography) and confirmed by renal histopathological analysis. These results suggest that specific biokinetic models should be developed to consider altered uranium excretion and retention in kidney due to nephrotoxicity. The threshold is between 0.25 and 1 mg/kg/day after repeated exposure to uranium via upper airways.

Safety evaluation of the food enzyme glucan 1,4-α-glucosidase from the non-genetically modified Aspergillus niger strain NZYM-BO

The food enzyme glucan 1,4-α-glucosidase (4-α-d-glucan α-glucohydrolase; EC 3.2.1.3) is produced with the non-genetically modified Aspergillus niger strain NZYM-BO by Novozymes A/S. It was considered free from viable cells of the production organism. It is intended to be used in seven food manufacturing processes: baking processes, brewing processes, cereal-based processes, distilled alcohol production, fruit and vegetable processing for juice production, production of dairy analogues and starch processing for the production of glucose syrups and other starch hydrolysates. Since residual amounts of total organic solids (TOS) are removed by distillation and during starch processing, dietary exposure was not calculated for these two food manufacturing processes. For the remaining five food manufacturing processes, dietary exposure to the food enzyme-TOS was estimated to be up to 2.97 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not indicate a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 1,920 mg TOS/kg bw per day, the highest dose tested, which, when compared with the estimated dietary exposure, resulted in a margin of exposure of at least 646. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and one match with a respiratory allergen was found. The Panel considered that, under the intended conditions of use, the risk of allergic reactions by dietary exposure to this food enzyme cannot be excluded (except for distilled alcohol production), but the likelihood is low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

High-Dose Primaquine Induces Proximal Tubular Degeneration and Ventricular Cardiomyopathy Linked to Host Cells Mitochondrial Dysregulation

Primaquine (PQ) is the only antimalarial medication used to eradicate many species of Plasmodium gametocytes and prevent relapse in vivax and ovale malarias. PQ metabolites induce oxidative stress and impair parasitic mitochondria, leading to protozoal growth retardation and death. Collateral damage is also presented in mammalian host cells, particularly erythrocytes, resulting in hemolysis and tissue destruction. However, the underlying mechanisms of these complications, particularly the mitochondria-mediated cell death of the host, are poorly understood. In the present study, toxicopathological studies were conducted on a rat model to determine the effect of PQ on affected tissues and mitochondrial toxicity. The results indicated that the LD₅₀ for PQ is 200 mg/kg. A high dose of PQ induced hemolytic anemia, elevated a hepatic enzyme (SGPT), and induced proximal tubular degeneration, ventricular cardiomyopathy, and mitochondrial dysregulation. In addition, PQ induced the upregulation of apoptosis-related proteins Drp-1 and caspase-3, with a positive correlation, as well as the pro-apoptotic mitochondrial gene expression of Bax, reflecting the toxic effect of high doses of PQ on cellular damage and mitochondrial apoptosis in terms of hepatotoxicity, nephrotoxicity, and cardiotoxicity. Regarding the risk/benefit ratio of drug administration, our research provides caution for the use of PQ in the treatment of malaria based on its toxicopathological effects.

Pulmonary toxicity of molybdenum disulphide after inhalation in mice

Molybdenum disulphide (MoS₂) is a constituent of many products. To protect humans, it is important to know at what air concentrations it becomes toxic. For this, we tested MoS₂ particles by nose-only inhalation in mice. Exposures were set to 13, 50 and 150 mg MoS₂/m³ (=8, 30 and 90 mg Mo/m³), corresponding to Low, Mid and High exposure. The duration was 30 min/day, 5 days/week for 3 weeks. Molybdenum lung-deposition levels were estimated based on aerosol particle size distribution measurements, and empirically determined with inductively coupled plasma-mass spectrometry (ICP-MS). Toxicological endpoints were body weight gain, respiratory function, pulmonary inflammation, histopathology, and genotoxicity (comet assay). Acellular reactive oxygen species (ROS) production was also determined. The aerosolised MoS₂ powder had a mean aerodynamic diameter of 800 nm, and a specific surface area of 8.96 m²/g. Alveolar deposition of MoS₂ in lung was estimated at 7, 27 and 79 µg/mouse and measured as 35, 101 and 171 µg/mouse for Low, Mid and High exposure, respectively. Body weight gain was lower than in controls at Mid and High exposure. The tidal volume was decreased with Low and Mid exposure on day 15. Increased genotoxicity was seen in bronchoalveolar lavage (BAL) fluid cells at Mid and High exposures. ROS production was substantially lower than for carbon black nanoparticles used as bench-mark, when normalised by mass. Yet if ROS of MoS₂ was normalised by surface area, it was similar to that of carbon black, suggesting that a ROS contribution to the observed genotoxicity cannot be ruled out. In conclusion, effects on body weight gain and genotoxicity indicated that Low exposure (13 mg MoS₂/m³, corresponding to 0.8 mg/m³ for an 8-hour working day) was a No Observed Adverse Effect Concentration (NOAEC,) while effects on respiratory function suggested this level as a Lowest Observed Adverse Effect Concentration (LOAEC).

Effects of short-term exposure to low doses of bisphenol A on cellular senescence in the adult rat kidney

Bisphenol A (BPA) is one of the primary chemicals produced by volume worldwide. Extensive literature has raised many concerns about its possible involvement in the pathogenesis of kidney diseases, but its contribution has not been extensively studied. During cellular senescence, the interference of lipofuscin with cellular functions promotes further senescence, causing cellular malfunction. Insulin-like growth factor-1 (IGF-1) plays an important protective role in the setting of kidney injury. The goal of the present work was to evaluate the effects of short-term treatment with low doses of BPA on cellular senescence in adult rat kidneys. Male Wistar rats were injected with vehicle (CONTROL group) or 50 or 500 μg/kg/day of BPA for 1 week (BPA50 and BPA500 groups, respectively). The kidneys were fixed in 4% buffered formaldehyde and embedded in paraffin. Immunohistochemical analyses were performed, and an immunoreactive score (IRS) was calculated. Lipofuscin autofluorescence was used for the study of cellular senescence. The renal cortex showed diffuse autofluorescent lipofuscin signal in the proximal convoluted tubules (PCTs) of males in the BPA50-treated (weak intensity) and BPA500-treated (strong intensity) groups, but not in CONTROL males. Labeling of cortical PCTs with anti-IGF-1 antibodies showed an IRS of 0 in the CONTROL group, but IRSs of 4 and 6 in the BPA50- and BPA500-treated groups, respectively. The present results suggest that low, "safe" doses of BPA induce renal injury, as measured by histological signs of renal changes, increased cellular senescence, and activation of cellular repair systems in PCTs.

Evaluating maternal exposure to an environmental per and polyfluoroalkyl substances (PFAS) mixture during pregnancy: Adverse maternal and fetoplacental effects in a New Zealand White (NZW) rabbit model

Mixtures of per- and polyfluoroalkyl substances (PFAS) are often found in drinking water, and serum PFAS are detected in up to 99% of the population. However, very little is known about how exposure to mixtures of PFAS affects maternal and fetal health. The aim of this study was to investigate maternal, fetal, and placental outcomes after preconceptional and gestational exposure to an environmentally relevant PFAS mixture in a New Zealand White (NZW) rabbit model. Dams were exposed via drinking water to control (no detectable PFAS) or a PFAS mixture for 32 days. This mixture was formulated with PFAS to resemble levels measured in tap water from Pittsboro, NC (10 PFAS compounds; total PFAS load = 758.6 ng/L). Maternal, fetal, and placental outcomes were evaluated at necropsy. Thyroid hormones were measured in maternal serum and kit blood. Placental gene expression was evaluated by RNAseq and qPCR. PFAS exposure resulted in higher body weight (p = 0.01), liver (p = 0.01) and kidney (p = 0.01) weights, blood pressure (p = 0.05), and BUN:CRE ratio (p = 0.04) in dams, along with microscopic changes in renal cortices. Fetal weight, measures, and histopathology were unchanged, but a significant interaction between dose and sex was detected in the fetal: placental weight ratio (p = 0.036). Placental macroscopic changes were present in PFAS-exposed dams. Dam serum showed lower T4 and a higher T3:T4 ratio, although not statistically significant. RNAseq revealed that 11 of the 14 differentially expressed genes (adj. p < 0.1) are involved in placentation or pregnancy complications. In summary, exposure elicited maternal weight gain and signs of hypertension, renal injury, sex-specific changes in placental response, and differential expression of genes involved in placentation and preeclampsia. Importantly, these are the first results to show adverse maternal and placental effects of an environmentally-relevant PFAS mixture in vivo.

Effects of dietary phosphorus concentration and phosphate salt form on renal tubule function in unilateral nephrectomized rats

Background: Excessive consumption of phosphorus (P) impairs renal tubule function; however, the effects of different dietary phosphate salts on chronic kidney disease (CKD) are unclear. Aim: To examine the effects of potassium dihydrogen phosphate (KH2PO4) and potassium tripolyphosphate (K5P3O10) and P concentration on renal function in a rat model of early CKD. Methods: Male sham-operated Sprague-Dawley rats were fed a diet containing KH2PO4 with a normal P level. Kidney injury was induced by unilateral nephrectomy (UNx), and the rats were divided into four groups fed dietary KH2PO4 or K5P3O10 with a normal (UNx-NKH, UNx-NKP) or high (UNx-HKH, UNx-HKP) P concentration, respectively, for 21 days. Results: UNx-NKH rats showed significantly lower creatinine clearance (CCr) and higher albumin (ALB) compared with those of sham rats, confirming UNx-induced kidney injury. The urinary levels of liver-type fatty acid-binding protein (L-FABP) and ALB were significantly higher in UNx-HKP rats than in UNx-HKH rats. However, other markers of renal tubule function, such as CCr, serum creatinine (CRE), calcium (Ca), and hormones, only differed among groups according to the P concentration and not the dietary phosphate salt form. Histological examination showed higher incidence and severity of tubulointerstitial lesions, tubule regeneration, tubule dilation, and calcification in the high-phosphorus than in the normal-phosphorus UNx groups. These changes were more severe in the UNx-HKP group compared with the UNx-HKH group. Conclusion: This study highlights the importance of controlling dietary P intake in terms of both concentration and source to prevent the progression of CKD.

Causes of Mortality and Profile of Spontaneous Tumors in Young CD-1 Mice

A retrospective study was performed to establish the causes of mortality and incidence patterns of tumors in young (<50 weeks) control CD-1® mice from Charles River Laboratories. Tumor incidences (fatal and nonfatal) and nonneoplastic causes of death observed during the first 50 weeks of the study were collected from 48 thirteen-week toxicity studies conducted between 2009 and 2018 and from 43 carcinogenicity studies conducted between 2005 and 2018. Thirteen-week studies had a mortality rate of 8/620 (1.3%) in males and 4/620 (0.65%) in females. The major factors contributing to death were integument lesions in males (3/8) and experimental procedure-related injuries in females (3/4). All tumors recorded were nonfatal. Bronchiolo-alveolar adenoma was the commonest tumor with the same incidence in both males and females (4/620, 0.65%); a single lymphoma (0.16%) and uterine leiomyosarcoma (1/620 0.16%) were reported in females. The mortality rates of males and females that died or were euthanized during the first 50 weeks in carcinogenicity studies were 192/2830 (6.8%) and 198/2830 (7%), respectively. The most common fatal tumor in this age group was lymphoma in both sexes, with an incidence of 18/192 (9.3%) and 41/198 (20.7%) in males and females, respectively. In males tumors were responsible for fewer deaths than in females (17% vs. 32.3%). The major nonneoplastic causes of death or moribundity were cutaneous lesions (44/192, 22.9%), and obstructive uropathy (39/192, 20.3%) in males, and chronic progressive nephropathy (40/198, 20.2%) in females. Only minor differences were evident compared to a similar study performed 15 years ago; these might reflect changes in terminology and diagnostic criteria, and stricter animal welfare endpoints.

Cyclam with a phosphinate-bis(phosphonate) pendant arm is a bone-targeting carrier of copper radionuclides

Ligands combining a bis(phosphonate) group with a macrocycle function as metal isotope carriers for radionuclide-based imaging and for treating bone metastases associated with several cancers. However, bis(phosphonate) pendant arms often slow down complex formation and decrease radiochemical yields. Nevertheless, their negative effect on complexation rates may be mitigated by using a suitable spacer between bis(phosphonate) and the macrocycle. To demonstrate the potential of bis(phosphonate) bearing macrocyclic ligands as a copper radioisotope carrier, we report the synthesis of a new cyclam derivative bearing a phosphinate-bis(phosphonate) pendant (H₅te1P^BP). The ligand showed a high selectivity to Cu^II over Zn^II and Ni^II ions, and the bis(phosphonate) group was not coordinated in the Cu^II complex, strongly interacting with other metal ions in solution. The Cu^II complex formed quickly, in 1 s, at pH 5 and at a millimolar scale. The complexation rates significantly differed under a ligand or metal ion excess due to the formation of reaction intermediates differing in their metal-to-ligand ratio and protonation state, respectively. The Cu^II-te1P^BP complex also showed a high resistance to acid-assisted hydrolysis (t_1/2 2.7 h; 1 M HClO₄, 25 °C) and was effectively adsorbed on the hydroxyapatite surface. H₅te1P^BP radiolabeling with [⁶⁴Cu]CuCl₂ was fast and efficient, with specific activities of approximately 30 GBq ⁶⁴Cu per 1 μmol of ligand (pH 5.5, room temperature, 30 min). In a pilot experiment, we further demonstrated the excellent suitability of [⁶⁴Cu]Cu^II-te1P^BP for imaging active bone compartments by dedicated small animal PET/CT in healthy mice and subsequently in a rat femoral defect model, in direct comparison with [¹⁸F]fluoride. Moreover, [⁶⁴Cu]Cu^II-te1P^BP showed a higher uptake in critical bone defect regions. Therefore, our study highlights the potential of [⁶⁴Cu]Cu^II-te1P^BP as a PET radiotracer for evaluating bone healing in preclinical and clinical settings with a diagnostic value similar to that of [¹⁸F]fluoride, albeit with a longer half-life (12.7 h) than ¹⁸F (1.8 h), thereby enabling extended observation times.

Aerobic exercise training combined or not with okra consumption as a strategy to prevent kidney changes caused by metabolic syndrome in Zucker rats

The complications of Metabolic Syndrome (MetS) include kidney disease, and most dialysis patients are diagnosed with MetS. The benefit of exercise training (ET) for MetS treatment is already well defined in the literature, but the antidiabetic and antihyperlipidemic benefits of okra (O) have been discovered only recently. The aim of this study was to evaluate the effects of O and/or ET supplementation on renal function and histology; serum urea and creatinine value; inflammation (IL-6, IL-10, TNF-α) and oxidative stress in renal tissue. For this, 32 Zucker rats (fa/fa) were randomly separated into four groups of 8 animals each: Metabolic Syndrome (MetS), MetS + Okra (MetS + O), MetS + Exercise Training (MetS + ET), and MetS + Exercise Training and Okra (MetS + ET + O), and 8 Zucker lean (fa/+) rats comprised the Control group (CTL). Okra was administered by orogastric gavage 2x/day (morning and night, 100 mg/kg) and ET performed on the treadmill, at moderate intensity, 1h/day, 5x/week for 6 weeks. Although the renal function was not altered, the animals with MetS showed greater fibrotic deposition accompanied by a worse stage of renal injury, in addition to increased kidney weight. Although all interventions were beneficial in reducing fibrosis, only ET combined with O was able to improve the degree of renal tissue impairment. ET improved the anti-inflammatory status and reduced nitrite levels, but the combination of ET and O was more beneficial as regards catalase activity. Okra consumption alone did not promote changes in inflammatory cytokines and oxidative stress in the kidney. In conclusion, ET combined or not with O seems to be beneficial in preventing the progression of renal disease when renal function is not yet altered.

Methyl-tert-butyl ether (MTBE): integration of rat and mouse carcinogenicity data with mode of action and human and rodent bioassay dosimetry and toxicokinetics indicates MTBE is not a plausible human carcinogen

Methyl-tert-butyl ether (MTBE) is a fuel oxygenate used in non-United States geographies. Multiple health reviews conclude that MTBE is not a human-relevant carcinogen, and this review provides updated mode of action (MOA), exposure, dosimetry and risk perspectives supporting those conclusions. MTBE is non-genotoxic and has large margins of exposure between blood concentrations at the overall rat 400 ppm inhalation NOAEL and blood concentrations in typical workplace or general population exposures. Non-cancer and threshold cancer hazard quotients range from a high of 0.046 for fuel-pump gasoline station attendants and are 100-1,000-fold lower for general population exposures. Cancer risks conservatively assuming genotoxicity for these same scenarios are all less than 1 × 10^-6. The onset of MTBE nonlinear toxicokinetics (TK) in rats at inhalation exposures less than 3,000 ppm, a dose that is also not practically achievable in fuel-use scenarios, indicates that high-dose specific male rat kidney and testes (3,000 and 8,000 ppm) and female mouse liver tumors (8000 ppm) are not quantitatively relevant to humans. Mode of action analyses also indicate MTBE male rat kidney tumors, and lesser so female mouse liver tumors, are not qualitatively relevant to humans. Thus, an integrated analysis of the toxicology, exposure/dosimetry, TK, and MOA data indicates that MTBE presents minimal human cancer and non-cancer risks.

Safety Assessment of L-β-Aminoisobutyric Acid (L-BAIBA): Subchronic Toxicity Study in Sprague Dawley Rats

L-3-Aminoisobutyric acid (L-BAIBA) is an endogenous compound in human metabolism when thymine and valine undergo catabolism. L-BAIBA represents one of the two isomers of BAIBA in biological systems. BAIBA has been shown to reduce body fat percentage via an increase in fatty acid oxidation and a decrease in hepatic lipogenesis. However, no toxicological effects of L-BAIBA in animals or humans have been established. The present study was designed to evaluate the safety and toxic potentials of this compound, where L-BAIBA was administered orally to Sprague Dawley rats at 100, 300, and 900 mg/kg/day for 90 days. No treatment-related adverse effects were observed in any of the treatment groups. Based on the results, the No-Observed-Adverse-Effect Level (NOAEL) of L-BAIBA was 900 mg/kg/day.

Petasites for Migraine Prevention: New Data on Mode of Action, Pharmacology and Safety. A Narrative Review

Petasins are the pharmacologically active ingredients of butterbur and of therapeutic benefit in the treatment of migraine and tension headaches. Here, we summarize the pharmacology, safety and clinical efficacy of butterbur in the prevention of migraine attacks and present new data on its mode of action. We review published literature and study reports on the safety and clinical efficacy of the butterbur root extract Petadolex® and report new findings on petasins in dampening nociception by desensitizing calcium-conducting TRP ion channels of primary sensory neurons. Importantly, butterbur diminishes the production of inflammatory mediators by inhibiting activities of cyclooxygenases, lipoxygenases and phospholipase A2 and desensitizes nociception by acting on TRPA1 and TRPPV1 ion channels. It inhibits the release of calcitonin-gene related peptide (CGRP) of meningeal afferents during migraine attacks. We also evaluated the safety of a butterbur root extract in repeated dose studies for up to 6 months. A no-observable-adverse-effect-level at 15-fold of the maximal clinical dose (3 mg/kg/day MCD) was established for rats. At supratherapeutic doses, i.e., 45–90-fold MCD, we observed bile duct hyperplasia, and mechanistic studies revealed regulations of solute carriers to likely account for bile duct proliferations. Additionally, liver function tests were performed in cultures of primary human hepatocytes and did not evidence hepatotoxicity at therapeutic butterbur level and with migraine co-medications. Lastly, in randomized, double-blinded and placebo-controlled trials with Petadolex® migraine attack frequency was reduced significantly at 150 mg/day, and no relevant abnormal liver function was reported. Together, butterbur is effective in the prevention of migraine attacks by blocking CGRP signaling.

Comparative analysis of hypertensive nephrosclerosis in animal models of hypertension and its relevance to human pathology. Glomerulopathy

Current research on hypertension utilizes more than fifty animal models that rely mainly on stable increases in systolic blood pressure. In experimental hypertension, grading or scoring of glomerulopathy in the majority of studies is based on a wide range of opinion-based histological changes that do not necessarily comply with lesional descriptors for glomerular injury that are well-established in clinical pathology. Here, we provide a critical appraisal of experimental hypertensive glomerulopathy with the same approach used to assess hypertensive glomerulopathy in humans. Four hypertensive models with varying pathogenesis were analyzed–chronic angiotensin II infused mice, mice expressing active human renin in the liver (TTRhRen), spontaneously hypertensive rats (SHR), and Goldblatt two-kidney one-clip rats (2K1C). Analysis of glomerulopathy utilized the same criteria applied in humans–hyalinosis, focal segmental glomerulosclerosis (FSGS), ischemic, hypertrophic and solidified glomeruli, or global glomerulosclerosis (GGS). Data from animal models were compared to human reference values. Kidneys in TTRhRen mice, SHR and the nonclipped kidneys in 2K1C rats had no sign of hyalinosis, FSGS or GGS. Glomerulopathy in these groups was limited to variations in mesangial and capillary compartment volumes, with mild increases in collagen deposition. Histopathology in angiotensin II infused mice corresponded to mesangioproliferative glomerulonephritis, but not hypertensive glomerulosclerosis. The number of nephrons was significantly reduced in TTRhRen mice and SHR, but did not correlate with severity of glomerulopathy. The most substantial human-like glomerulosclerotic lesions, including FSGS, ischemic obsolescent glomeruli and GGS, were found in the clipped kidneys of 2K1C rats. The comparison of affected kidneys to healthy control in animals produces lesion values that are numerically impressive but correspond to mild damage if compared to humans. Animal studies should be standardized by employing the criteria and classifications established in human pathology to make experimental and human data fully comparable for comprehensive analysis and model improvements.

Research-Relevant Conditions and Pathology of Laboratory Mice, Rats, Gerbils, Guinea Pigs, Hamsters, Naked Mole Rats, and Rabbits

Animals are valuable resources in biomedical research in investigations of biological processes, disease pathogenesis, therapeutic interventions, safety, toxicity, and carcinogenicity. Interpretation of data from animals requires knowledge not only of the processes or diseases (pathophysiology) under study but also recognition of spontaneous conditions and background lesions (pathology) that can influence or confound the study results. Species, strain/stock, sex, age, anatomy, physiology, spontaneous diseases (noninfectious and infectious), and neoplasia impact experimental results and interpretation as well as animal welfare. This review and the references selected aim to provide a pathology resource for researchers, pathologists, and veterinary personnel who strive to achieve research rigor and validity and must understand the spectrum of "normal" and expected conditions to accurately identify research-relevant experimental phenotypes as well as unusual illness, pathology, or other conditions that can compromise studies involving laboratory mice, rats, gerbils, guinea pigs, hamsters, naked mole rats, and rabbits.

Preclinical safety assessments of nicotinamide riboside hydrogen malate

Nicotinamide riboside (NR) is an analog of vitamin B3, which is naturally present in trace amounts in selected foods. Several B3 analogs are known precursors in the synthesis of nicotinamide adenine dinucleotide, including nicotinic acid (niacin) and nicotinamide (niacinamide). The safety of nicotinamide riboside hydrogen malate (NRHM), a salt of NR, was assessed in a bacterial reverse mutagenesis assay (Ames), in vitro micronucleus assay in human peripheral lymphocytes, a 14-day acute toxicology test (Sprague-Dawley rats), and a 90-day sub-chronic toxicology study in Sprague-Dawley rats. Based on the results of the 14-day study, the 90-day sub-chronic study was conducted comparing oral NRHM at 1000, 1500, and 3000 mg/kg/day with a vehicle control. No genotoxicity was observed. There were no mortalities or clinical observations attributed to the NRHM test substance administration over the course of the study. The no-observed-adverse effect level for NRHM was determined to be 3000 mg/kg bw/day in the female rats but 2000 mg/kg bw/day in the male rats due to a significantly lower body weight in males at the high dose. The results of this study imply that NRHM can be manufactured at a high level of purity, is not genotoxic, and is well-tolerated in in Sprague-Dawley rats.

Confounders for kidney carcinogenesis in rodent cancer bioassays

In the long-term safety testing of chemicals for carcinogenicity the toxicologist needs to be aware of a number of scenarios where renal tubule tumors, or their precursors, arise that are not due to a carcinogenic action of the test article. Situations producing false positive results in the kidney include exacerbation of chronic progressive nephropathy (CPN) in rats, confusion of atypical tubule hyperplasia (the obligate precursor of renal tubule tumor) with foci of benign CPN-related renal tubule cell proliferation, inclusion of spontaneous tumor entities, such as the amphophilic-vacuolar tumor, in the test article tumor count, the possibility of a link between spontaneous forms of tubule dilatation and renal tubule tumor formation in mice, and the supposed predictivity of chemically-induced karyomegaly for renal carcinogenicity in both rats and mice. Examples of these misleading situations are described and discussed.

Treadmill Exercise Training Ameliorates Functional and Structural Age-Associated Kidney Changes in Male Albino Rats

Aging is a biological process that impacts multiple organs. Unfortunately, kidney aging affects the quality of life with high mortality rate. So, searching for innovative nonpharmacological modality improving age-associated kidney deterioration is important. This study aimed to throw more light on the beneficial effect of treadmill exercise on the aged kidney. Thirty male albino rats were divided into three groups: young (3-4 months old), sedentary aged (23-24 months old), and exercised aged (23-24 months old, practiced moderate-intensity treadmill exercise 5 days/week for 8 weeks). The results showed marked structural alterations in the aged kidney with concomitant impairment of kidney functions and increase in arterial blood pressure with no significant difference in kidney weight. Also, it revealed that treadmill exercise alleviated theses effects in exercised aged group with reduction of urea and cystatin C. Exercise training significantly decreased glomerulosclerosis index, tubular injury score, and % area of collagen deposition. Treadmill exercise exerted its beneficial role via a significant reduction of C-reactive protein and malondialdehyde and increase in total antioxidant capacity. In addition, exercise training significantly decreased desmin immunoreaction and increased aquaporin-3, vascular endothelial growth factor, and beclin-1 in the aged kidney. This study clarified that treadmill exercise exerted its effects via antioxidant and anti-inflammatory mechanisms, podocyte protection, improving aquaporin-3 and vascular endothelial growth factor expression, and inducing autophagy in the aged kidney. This work provided a new insight into the promising role of aerobic exercise to ameliorate age-associated kidney damage.

Safety Evaluation for Restorin® NMN, a NAD+ Precursor

NAD+ is an abundant molecule in the body and vital to all living cells. NAD+ levels decline with age, and this decline correlates with age-related diseases. Therefore, sustaining NAD+ levels offers potential benefits to healthspan and longevity. Here we conducted toxicity studies to evaluate the safety of Restorin® NMN, a high purity form of the direct NAD+ precursor, β-nicotinamide mononucleotide (NMN). Based on the preliminary toxicity study and a 14-days repeated dose toxicity study at a higher dose level exposure, Restorin® NMN was administered orally to Sprague-Dawley rats for 91 days followed by a 14-days recovery period. The oral doses of 500, 1,000, and 2000 mg/kg/day were compared. There were no test item-related findings that could be considered adverse events in animals dosed at 500 mg/kg/day. The findings in the Restorin® NMN high dose group (2000 mg/kg/day) were similar to the reference item (Nicotinamide Riboside Chloride) dosed at 1740 mg/kg/day: reduced body weight, reductions in body weight gains, and diminished food consumption. In conclusion, the No-Observed-Adverse-Effect-Level (NOAEL) for Restorin® NMN is 1,000 mg/kg/day in female rats and 500 mg/kg/day in male rats, and the Low-Observed-Adverse-Effect-Level (LOAEL) for Resotrin® NMN is 2000 mg/kg/day.

Aristolochic acid I promoted clonal expansion but did not induce hepatocellular carcinoma in adult rats

Aristolochic acid I (AAI) is a well-known nephrotoxic carcinogen, which is currently reported to be also associated with hepatocellular carcinoma (HCC). Whether AAI is a direct hepatocarcinogen remains controversial. In this study we investigated the association between AAI exposure and HCC in adult rats using a sensitive rat liver bioassay with several cofactors. Formation of glutathione S-transferase placental form-positive (GST-P+) foci was used as the marker for preneoplastic lesions/clonal expansion. We first conducted a medium-term (8 weeks) study to investigate whether AAI had any tumor-initiating or -promoting activity. Then a long-term (52 weeks) study was conducted to determine whether AAI can directly induce HCC. We showed that oral administration of single dose of AAI (20, 50, or 100 mg/kg) in combination with partial hepatectomy (PH) to stimulate liver proliferation did not induce typical GST-P+ foci in liver. In the 8-week study, only high dose of AAI (10 mg · kg-1 · d-1, 5 days a week for 6 weeks) in combination with PH significantly increased the number and area of GST-P+ foci initiated by diethylnitrosamine (DEN) in liver. Similarly, only high dose of AAI (10 mg· kg-1· d-1, 5 days a week for 52 weeks) in combination with PH significantly increased the number and area of hepatic GST-P+ foci in the 52-week study. No any nodules or HCC were observed in liver of any AAI-treated groups. In contrast, long-term administration of AAI (0.1, 1, 10 mg· kg-1· d-1) time- and dose-dependently caused death due to the occurrence of cancers in the forestomach, intestine, and/or kidney. Besides, AAI-DNA adducts accumulated in the forestomach, kidney, and liver in a time- and dose-dependent manner. Taken together, AAI promotes clonal expansion only in the high-dose group but did not induce any nodules or HCC in liver of adult rats till their deaths caused by cancers developed in the forestomach, intestine, and/or kidney. Findings from our animal studies will pave the way for further large-scale epidemiological investigation of the associations between AA and HCC.

Differential Uptake of Antisense Oligonucleotides in Mouse Hepatocytes and Macrophages Revealed by Simultaneous Two-Photon Excited Fluorescence and Coherent Raman Imaging

Antisense oligonucleotides (ASOs), a novel paradigm in modern therapeutics, modulate cellular gene expression by binding to complementary messenger RNA (mRNA) sequences. While advances in ASO medicinal chemistry have greatly improved the efficiency of cellular uptake, selective uptake by specific cell types has been difficult to achieve. For more efficient and selective uptake, ASOs are often conjugated with molecules with high binding affinity for transmembrane receptors. Triantennary N-acetyl-galactosamine conjugated phosphorothioate ASOs (GalNAc-PS-ASOs) were developed to enhance targeted ASO delivery into liver through the hepatocyte-specific asialoglycoprotein receptor (ASGR). We assessed the kinetics of uptake and subsequent intracellular distribution of AlexaFluor 488 (AF488)-labeled PS-ASOs and GalNAc-PS-ASOs in J774A.1 mouse macrophages and primary mouse or rat hepatocytes using simultaneous coherent anti-Stokes Raman scattering (CARS) and two-photon fluorescence (2PF) imaging. The CARS modality captured the dynamic lipid distributions and overall morphology of the cells; two-photon fluorescence (2PF) measured the time- and dose-dependent localization of ASOs delivered by a modified treatment of suspension cells. Our results show that in macrophages, the uptake rate of PS-ASOs did not significantly differ from that of GalNAc-PS-ASOs. However, in hepatocytes, GalNAc-PS-ASOs exhibited a peripheral uptake distribution compared to a polar uptake distribution observed in macrophages. The peripheral distribution correlated with a significantly larger amount of internalized GalNAc-PS-ASOs compared to the PS-ASOs. This work demonstrates the relevance of multimodal imaging for elucidating the uptake mechanism, accumulation, and fate of different ASOs in liver cells that can be used further in complex in vitro models and liver tissues to evaluate ASO distribution and activity.

Post-mortem assessment of vimentin expression as a biomarker for renal tubular regeneration following acute kidney injury

BACKGROUND

Acute kidney injury (AKI) is a common cause of morbidity and mortality. It mainly targets the renal tubular epithelium with pathological changes, referred to as acute tubular injury. The latter is followed by a regenerative response that is difficult to visualize on routine hematoxylin and eosin (H&E) stains. In this study, we examined the regenerative capacity of renal tubules by correlating vimentin (VIM) immunohistochemical (IHC) expression and pathological findings of AKI and renal tubular regeneration (RTR) on H&E.

METHODS

We reviewed 23 autopsies performed in the clinical setting of AKI and RTR. VIM expression was scored in the renal cortical tubular epithelium using a statistical cutoff ≥ 3% for high expression and < 3% for low expression.

RESULTS

Of the 23 kidney tissues examined, seven (30.4%) had low VIM expression, and 16 (69.6%) had high VIM expression. Kidney tissues with evidence of AKI and RTR had significantly higher VIM expression. Renal peritubular microenvironment features showing regenerative changes on H&E were associated with high VIM expression. In the univariate model, kidney tissues with RTR were 18-fold more likely to have high VIM expression.

CONCLUSIONS

In conclusion, our findings suggest that VIM could serve as an IHC marker for RTR following AKI. However, correlation with H&E findings remains critical to excluding chronic tubular damage. Collectively, our preliminary results pave the way for future studies including a larger sample size to validate the use of VIM as a reliable biomarker for RTR.

Interaction between ZnO Nanoparticles and Albumin and Its Effect on Cytotoxicity, Cellular Uptake, Intestinal Transport, Toxicokinetics, and Acute Oral Toxicity

Zinc oxide (ZnO) nanoparticles (NPs) are used as zinc supplements due to the nutritional value of Zn. The toxicity of ZnO NPs in the food industry is required to be elucidated because they have large surface area and high reactivity compared with bulk-sized materials and have potentials to interact with food matrices, which may lead to different biological responses. In this study, interactions between ZnO NPs and food proteins (albumin, casein, and zein) were evaluated by measuring changes in physicochemical property, fluorescence quenching ratios, and structural protein stability compared with ZnO interaction with glucose, the most interacted saccharide in our previous report. The interaction effects on cytotoxicity, cellular uptake, intestinal transport, toxicokinetics, and acute oral toxicity were also investigated. The results demonstrate that interaction between ZnO and albumin reduced hydrodynamic diameters, but increased cytotoxicity, cellular uptake, and intestinal transport in a similar manner to ZnO interaction with glucose, without affecting primary structural protein stability and toxicokinetic behaviors. Hematological, serum biochemical, and histopathological analysis reveal no toxicological findings after orally administered ZnO NPs interacted with albumin or glucose in rats for 14 consecutive days, suggesting their low oral toxicity. In conclusion, the interactions between ZnO NPs and food proteins modulate in vitro biological responses, but do not affect in vivo acute oral toxicity. Further study is required to ascertain the interaction effects on chronic oral toxicity.