Subchronic Study Research Articles

Safety Evaluation of Amaranth Extract by Acute, Sub-Chronic and Chronic Exposure in Rats

Amaranth is one of the popularly grown leafy vegetables in tropical regions globally and contains a large amount of nitrate. The present study's objective was evaluation of acute and repeated dose toxicity of amaranth extract as per the OECD guidelines. The acute oral toxicity was conducted in 6 female rats (150-170 g; 8-10 Weeks old) as per OECD 423 guidelines. The amaranth extract had no adverse/toxic effects and no mortality was noted at the dose of 2000mg/kg. The oral LD50, therefore, was considered greater than 2000mg/kg. The sub-chronic (28-day repeated dose) toxicity was studied in 40 rats (150-170 g; 8-10 Weeks old) as per OECD 407 guidelines whereas chronic (365-days repeated dose) toxicity study was conducted in 200 rats (150-170 g; 8-10 Weeks old) as per OECD 452 guidelines. Sub-chronic study confirmed the safety of amaranth extract at the highest dose of 1000 mg/kg/day. The 1000 mg/kg in rats was considered as NOEL (No Observed Adverse Effect Level). The chronic toxicity study established a NOEL of 180 mg/kg in rats. In the repeated dose toxicity studies, body weight, food consumption, blood profile, biochemistry parameters and histopathology of major organs were similar in test and control groups. The current study results indicated that amaranth extract was safe upon acute, sub-chronic and chronic administration in rats, under testing conditions and at dose levels employed.

Ameliorative effect of Tinospora cordifolia stem aqueous extract on Hematological parameters of wistar rat against HgCl2 induced toxicity

Blood is crucial for the human body's health and survival. It carries out a variety of functions, including as delivering nutrients and oxygen. RBCs, WBCs, plasma, and platelets are the blood's major four constituents. It serves as a pathological sign for the condition of animals under different situations and toxicant exposure. This work aimed to explore the in vivo therapeutic mechanism of Tinospora cordifolia aqueous extracts against the haematotoxic effects of HgCl2. Ameliorative effect of T.cordifolia aqueous extract was evaluated in two groups of rats, including a treated group and a control group. The treated group was divided into following subgroups, I: HgCl2 treated, subgroup II: HgCl2 + T. cordifolia treated, subgroup III: T. cordifolia treated. These treated subgroups were further divided into 5 set of rats, one for acute (1d), three for sub-acute (7, 14 and 28ds), and one for sub-chronic (60 ds) study. The controls were run simultaneously. Male Wistar rats were given aqueous extracts of T. cordifolia (400 mg/kg body weight, orally, once daily) along with HgCl2 treatments. Dose of HgCl2 administered to animals after calculation of LD50 (25 mg/kg body weight). Animals used in acute, sub-acute, and sub-chronic studies of mercuric chloride received 1/10, 1/50, and 1/100 of the calculated LD50. This corresponds to 2.5, 0.5 and 0.25 mg/kg respectively. In mercury-treated mice, significant reductions in WBC, RBC, Hb, PCV and platelet count were also observed. These HgCl2-related effects were circumvented by regular intake of T. cordifolia aqueous extract. These results show that T. cordifolia protects against HgCl2 poisoning.

Acute and Subchronic Toxicity Assessment of Conventional Soxhlet Cymbopogon citratus Leaves Extracts in Sprague-Dawley Rats.

In Ghana, Cymbopogon citratus leaves together with guava, pawpaw, and lime are processed into a decoction to treat fever. To encourage its usage, preclinical validation of the safety profile of the plant is required. The acute and subchronic toxicities of the conventional Soxhlet ethanolic Cymbopogon citratus leaves extract in Sprague-Dawley rats were investigated. Pulverized Cymbopogon citratus leaves were extracted with 98% ethanol using the conventional Soxhlet extraction (CSE) method and dried. In the acute toxicity study, a single dose of 5000 mg/kg body weight was administered to six female Sprague-Dawley rats and 1 ml/100 g body weight normal saline to control (6) once, and signs of toxicity were observed every hour for the first 12 hr, 24 hr, and 48 hr through to 14 days. In the subchronic study, the treatment groups were administered 200 mg/kg, 600 mg/kg, and 1200 mg/kg, respectively, of the CSE C. citratus leaves extract for six weeks. Analyses were conducted on the blood, urine, and serum samples of the rats. Histopathological examination of the liver, heart, kidney, spleen, and lungs was carried out at termination. Analysis of variance (ANOVA) was performed to determine statistically significant differences between the test and control rats at P < 0.05. The results revealed that there were no statistically significant differences (p > 0.05) in the urinalysis and haematological analysis between control and test rats over the treatment period. Similarly, CSE C. citratus leaves extract did not induce any significant biochemical changes in the treatment group; however, there was a weight loss effect on the treated rats. There were no noticeable morphological changes in the heart, liver, spleen, lung, and kidney of the test rats compared to the control. CSE ethanolic C. citratus leaves extract has a weight loss effect, and long-term administration of the extract may not cause any organ-specific toxicity to the consumers.

Progesterone-Induced Hyperphagia is Attenuated by &lt;i&gt;Myrica nagi&lt;/i&gt; through Dopaminergic and Serotonergic Modulation in Female Mice

Regulation of feeding behavior to control obesity is an alternative line of research for the treatment of obesity and diabetes. Compared to other models of obesity, the progesterone-induced obesity model is more specific to the female population; it focuses on the eating behavior and behavioral and emotional changes associated with progesterone. We aimed to study the changes in feeding behavior upon progesterone administration and the effects of Myrica nagi Thunb (Myricaceae) extracts on these changes. Further, this study aimed to provide insights into the progesterone-induced hyperphagia modulated by serotonergic and dopaminergic systems. In this study, experimental obesity was induced in female mice by treating with a high dose of progesterone for 28 days (sub-chronic study) followed by the assessment of parameters such as food consumption behavior, behavioral parameters including ambulatory movements, rearing, and grooming, and biochemical parameters such as lipid profile (total cholesterol, triglycerides, high-density lipoprotein, and low-density lipoprotein), liver parameters (alkaline phosphatase and serum glutamic pyruvic transaminase), serotonin and dopamine levels, and liver histopathology. The sub-chronic administration of progesterone, via the subcutaneous route, induced significant hyperphagia and promoted fat accumulation. Even though we did not find significant differences in food intake between mice in the control group and progesterone-treated groups, the final weight in the progesterone-administered groups increased, signifying the impact of this progesterone-induced obesity model. Treatment with MEMN extract reversed the progesterone-induced effects suggesting that herbal extracts can be exploited as serotonergic and dopaminergic agents for the treatment of progesterone-induced eating disorders, especially in the female population.

Evaluation of acute, subacute, and subchronic toxicity of a hepatoprotective herbal formulation

BackgroundThe possible toxicity of natural products must be tested before being used in the market. The present work aimed to evaluate acute, subacute, and subchronic toxicity of an herbal formulation containing Anethum graveolens, Cynara scolymus, Citrus aurantium, Portulaca oleracea, and Silybum marianum. Material and methodsAcute toxicity (2000 mg/kg, single dose) and sub-acute toxicity (600 and 1200 mg/kg/day, 4 weeks) tests were performed on female and male rats according to OECD 423 and OECD 407 guidelines, respectively. In the subchronic study (12 weeks), the animals were divided into three groups (6 females and 6 males per group): control, low-dose group (food supplemented with 300 mg/kg of the herbal product), and high-dose group (600 mg/kg). ResultsThe herbal product at a single dose of 2000 mg/kg did not induce mortality for 14 days. In the sub-acute study, administration of the product for 28 days at 1200 mg/kg/day had no effect on survival, appetite (water and food consumption), body weight, serum biochemical parameters (BUN, creatinine, AST, ALT, ALP, bilirubin, albumin), histology of vital organs (liver, kidney, heart, brain), and hematological markers related to erythrocyte, platelet, and leukocyte. Similarly, in the subchronic study, the product did not induce mortality, change in histology of the vital organs, or alteration in hematological or biochemical parameters (except for an increase in ALP in female rats received 600 mg/kg). ConclusionThe formulated product shows no signs of toxicity in rats up to 2000 mg/kg, 1200 mg/kg, and 600 mg/kg in acute, subacute, and subchronic phases, respectively. It is suggested to monitor ALP levels in females in case of long-term use of the product.

Safety evaluation of INFAT® PLUS: Acute, genetic, teratogenic, and subchronic (90-day) toxicity studies

INFAT®PLUS, is a sn-2 palmitate enriched fat ingredient intended for infant formula. A battery of toxicological studies was conducted in accordance with the Food Safety Toxicological Assessment GB-15193 (China), to confirm the safety of INFAT®PLUS. In the acute oral toxicity test, the LD50 of INFAT® PLUS was higher than 53.4 g /kg BW and 26.7 g/kg BW for ICR mice and SD rats, respectively. In a subchronic study, INFAT® PLUS was administered by oral gavage to SD rats with maximal daily dose of 8.90 g/kg BW for 90 days. No treatment-related clinical signs or mortalities were observed. The no-observed-adverse-effect level (NOAEL) was set at 8.90 g/kg BW. Similarly, no evidence of genotoxicity effect was noted in several in vitro and in vivo tests, including bacterial reverse mutation (Ames) test, mouse erythrocyte micronucleus test, and chromosome aberration test of mouse spermatogonia/spermatocyte. For the teratogenic evaluations, no toxicological signs were observed in both pregnant SD rat and fetuses, and the NOAEL of INFAT® PLUS was determined to be 8.90 g/kg BW. Based on the obtained results we concluded that INFAT® PLUS was found non-toxic under the experimental conditions, and the totality of the safety data supports its use for infant nutrition.

Subchronic feeding study of glyphosate-tolerant maize GG2 with the gr79-epsps and gat genes in Wistar Han RCC rats

The genetically modified (GM) maize GG2 contains gr79-epsps and gat genes, conferring glyphosate tolerance. The present study aimed to investigate potential effects of maize GG2 in a 90-day subchronic feeding study on Wistar Han RCC rats. Maize grains from GG2 or non-GM maize were incorporated into diets at concentrations of 25% and 50% and administered to Wistar Han RCC rats (n = 10/sex/group) for 90 days. The basal-diet group of rats (n = 10/sex/group) were fed with common commercialized rodent diet. Compared with rats fed with the corresponding non-GM maize and the basal-diet, no biologically relevant differences were observed in rats fed with the maize GG2, according to the results of body weight/gain, feed consumption/utilization, clinical signs, mortality, ophthalmology, clinical pathology (hematology, prothrombin time, urinalysis, serum chemistry), organ weights, and gross and microscopic pathology. Under the conditions of this study, these results indicated that maize GG2 is as safe as the non-GM maize in this 90-day feeding study.

The Nonclinical Assessment of Trans-1,3,3,3-tetrafluoropropene (HFO-1234ze (E)), a Near Zero Global Warming Potential Propellant for Use in Metered Dose Inhalation Products.

HFO-1234ze (E) is proposed as a near zero global warming propellant for use in metered dose inhaled (MDI) products. This paper describes the non-clinical safety assessment in mice, rats, and dogs and supplements previously reported data (genetic toxicology, short-term toxicology, and reproductive toxicology). In all species, HFO-1234ze (E) was only detectable in blood for a short period after dosing with no evidence of accumulation. HFO-1234ze (E) was without any toxicological effects at very high doses in subchronic (13-week mouse) and chronic (39-week dog) studies. Chronic (26-week) administration to rats at very high doses was associated with an exacerbation of rodent progressive cardiomyopathy, a well-documented background finding in rodents. In a 2-generation study, extremely high doses were associated with the early euthanasia of some lactating female rats. This finding was considered to be significantly influenced by a state of negative energy balance, reflecting the specific vulnerability of rats during lactation. These findings are considered to not pose a risk to humans with typical MDI use given they occurred at doses which far exceed those expected in patients. Overall, the nonclinical safety data for HFO-1234ze (E) support its further development as an MDI propellant.

Okadaic Acid Is at Least as Toxic as Dinophysistoxin-1 after Repeated Administration to Mice by Gavage.

Okadaic acid (OA) and its analogues cause diarrhetic shellfish poisoning (DSP) in humans, and risk assessments of these toxins require toxicity equivalency factors (TEFs), which represent the relative toxicities of analogues. However, no human death by DSP toxin has been reported, and its current TEF value is based on acute lethality. To properly reflect the symptoms of DSP, such as diarrhea without death, the chronic toxicity of DSP toxins at sublethal doses should be considered. In this study, we obtained acute oral LD50 values for OA and dinophysistoxin-1 (DTX-1) (1069 and 897 μg/kg, respectively) to set sublethal doses. Mice were treated with sublethal doses of OA and DTX-1 for 7 days. The mice lost body weight, and the disease activity index and intestinal crypt depths increased. Furthermore, these changes were more severe in OA-treated mice than in the DTX-1-treated mice. Strikingly, ascites was observed, and its severity was greater in mice treated with OA. Our findings suggest that OA is at least as toxic as DTX-1 after repeated oral administration at a low dose. This is the first study to compare repeated oral dosing of DSP toxins. Further sub-chronic and chronic studies are warranted to determine appropriate TEF values for DSP toxins.

Biochemical and Toxicological Activity of Guiera senegalensis Leaves Extract

Guiera senegalensis (“Senegal guiera” in English; “Sabara” in Hausa) (Combretaceae) is traditionally used for various purposes in Africa and other parts of the world with little or no scientific basis. It is thus the aim of this research to evaluate its biochemical and toxicity effects for its medicinal properties, safety, efficacy of treatment, and the optimum dose. The study qualitatively screened for phytochemicals, acute toxicity (LD50) and sub-chronic toxicity indices in the ethylacetate extract of the plant. The result of phytochemical screening revealed G. senegalensis ethylacetate leaf extract to contain some important phytochemical compounds that may attribute to the biochemical properties possessed by the plant. The result of acute toxicity study showed that the plant is practically non-toxic (oral LD50&gt;5000mg/kg) when used for a short period of time and some signs of toxicity on heart in sub-chronic study (on long term of use). Also, the Haematological results indicated that the plant may have some effects on the immune system, might have caused an increase in RBC and haemoglobin production, and may also enhance O2 – transport capacity of the blood. Guiera senegalensis should therefore be used with care when used for a long period of time.

Reproducibility of organ-level effects in repeat dose animal studies

This work estimates benchmarks for new approach method (NAM)performance in predictingorgan-level effects in repeat dose studies of adult animals based on variability in replicate animal studies. Treatment-related effect values from theToxicityReference database (v2.1)for weight, gross, or histopathological changes in the adrenal gland, liver, kidney, spleen, stomach, and thyroid were used. Rates of chemical concordance among organ-level findings in replicate studies, definedbyrepeated chemical only, chemical and species, or chemical and study type, were calculated. Concordancewas 39–88%, depending on organ, and was highest within species.Variance in treatment-related effect values, including lowest effect level (LEL) values and benchmark dose (BMD) valueswhen available, was calculated by organ. Multilinear regression modeling,usingstudy descriptorsof organ-level effect values as covariates, was used to estimate total variance, mean square error(MSE), and root residual mean square error (RMSE). MSE values, interpreted as estimates of unexplained variance, suggeststudydescriptorsaccountedfor52–69% of totalvariance inorgan-levelLELs.RMSE ranged from0.41 to 0.68 log10-mg/kg/day. Differences between organ-level effects from chronic (CHR) and subchronic (SUB) dosing regimens were also quantified. Odds ratios indicated CHR organ effects were unlikely if the SUB study was negative. Mean differences of CHR - SUB organ-level LELs ranged from − 0.38 to − 0.19 log10mg/kg/day; the magnitudes of these mean differences were less than RMSE for replicate studies. Finally, in vitro to in vivo extrapolation (IVIVE) was employed to compare bioactive concentrations from in vitro NAMs for kidney and liver to LELs. The observed mean difference between LELs and mean IVIVE dose predictions approached 0.5 log10-mg/kg/day, but differences by chemical ranged widely. Overall, variability in repeat dose organ-level effects suggests expectations for quantitative accuracy of NAM prediction of LELs should be at least ± 1 log10-mg/kg/day, with qualitative accuracy not exceeding 70%.

749-P: Selection of BI 456906 as a Dual GCGR/GLP-1R Agonist Based on In Vitro Potency and In Vivo Target Engagement Biomarkers

Glucagon (GCG) and glucagon-like peptide 1 (GLP-1) are peptide hormones that pharmacologically regulate bodyweight by increasing energy expenditure and reducing energy intake, respectively. Several dual (GCG receptor [GCGR]/GLP-1 receptor [GLP-1R]) agonistic peptides are in clinical development for obesity. We describe preclinical data leading to selection of BI 456906 as a dual agonist. Functional potencies of the compounds were determined in CHO-K1 cells stably expressing human GCGR and GLP-1R. EC50 for GCGR mediated cAMP increase were 0.52 nM for BI 456906, 0.92 nM for BI 456908 and 0.44 nM for BI 456987. EC50 for GLP-1R engagement were 0.33 nM, 0.61 nM and 1.43 nM, respectively. Upon acute, single dosing to lean mice, engagement of the GCGR and GLP-1R was determined by testing for improvement in oral glucose tolerance (30 nmol/kg) and increase in plasma FGF-21 and liver nicotinamide N-methyltransferase mRNA expression (100 nmol/kg), respectively. Specificity of the biomarkers was confirmed using the selective GLP-1R agonist semaglutide and GLP-1R knockout mice. Bodyweight and glucose lowering (HbA1c) efficacies were investigated in subchronic dosing studies in diet-induced obese (DIO) and diabetic (db/db) mice, respectively. In DIO mice, BI 456906 (30 nmol/kg qd), BI 456908 (30 nmol/kg qd) and BI 456897 (10 nmol/kg qd) achieved bodyweight lowering from baseline of 25%, 27%, and 26%, respectively. In db/db mice, BI 456906 and BI 456908 (10 and 20 nmol/kg qd) substantially lowered HbA1c (0.4-0.6%); no clear effect was observed for BI 456897 (3 and 7 nmol/kg qd). As a balanced GCGR/GLP-1R agonist with robust in vivo efficacy BI 456906 (30 nmol/kg qd) was further characterized, and superior bodyweight lowering (32% vs 27%; p&amp;lt;0.05) was seen versus a maximally effective semaglutide dose (100 nmol/kg qd). This was attributed to an increase in energy expenditure. The selected candidate, BI 456906, is currently in clinical development in people with obesity and NASH. Disclosure R.Augustin: None. L.Thomas: Employee; Boehringer Ingelheim Pharma GmbH&amp;Co.KG. T.Zimmermann: Employee; Boehringer Ingelheim Pharma GmbH&amp;Co.KG. E.Simon: Employee; Boehringer Ingelheim Pharma GmbH&amp;Co.KG. W.Rist: None. I.Uphues: Employee; Boehringer Ingelheim Pharma GmbH&amp;Co.KG. W.Reindl: None. T.Klein: Employee; Boehringer Ingelheim Pharma GmbH&amp;Co.KG. H.Neubauer: None. Funding Zealand Pharma A/S; Boehringer Ingelheim

Toxicological Study of n-hexane and Chloroform Extracts of Lantana camara L. in Experimental Animals

Abstract: Aim: The aim of the current study is to investigate the acute, sub-acute and sub-chronic toxicity study of extracts (n-hexane and chloroform) of L. camara in Wistar rats. Materials and Methods: HPTLC and GC-MS analysis were carried out to analyze different constituents present in L. camara extract. Acute toxicity study was conducted as per OECD 420 guidelines, while sub-acute and sub-chronic studies were conducted according to OECD 407 and 408 guidelines respectively. Toxicopathological effects of both extracts were tested with the help of hemotoxylin and eosin staining of vital organs (liver, kidney, brain, testes, and ovaries) in experimental animals. Antioxidant and behavioral tests were also conducted on both the extracts, so as to evaluate the possible effects of toxicity. Results: The toxicity investigation of chloroform and n-hexane extracts exhibits no toxicity in terms of hematological (p<0.01) and biochemical parameters (p<0.05). Histopathological sections also confirmed the non-toxic effects on the liver, brain, kidney and on reproductive organs. Conclusion: The n-hexane and chloroform extracts of L. camara can be safely used for therapeutic purposes. Keywords: Lantana camara, GC-MS, HPTLC, Toxicity, Histopathology, Antioxidant, PI uptake.

Toxicology and carcinogenesis studies of an isomeric mixture of tris(chloropropyl) phosphate administered in feed to Sprague Dawley (Hsd:Sprague Dawley SD) rats and B6C3F1/N mice.

Tris(chloropropyl) phosphate (TCPP) is used as a flame retardant in textiles, furniture foam, and other related products. In addition, it is manufactured for use in construction materials, electronic products, paints, coatings, and adhesives. Several flame retardants, including structurally similar organohalogen compounds, have been removed from products in commerce due to toxicity concerns, and TCPP has been proposed as a replacement flame retardant for use in these products. An anticipated increase in use of TCPP has generated concerns for increased human exposure through oral, dermal, and inhalation routes; however, publicly available toxicity data are scarce. The U.S. Consumer Product Safety Commission therefore requested that the National Toxicology Program (NTP) form a research program on TCPP to conduct subchronic and chronic exposure studies in rats and mice for hazard identification and characterization information. Because TCPP is commercially available as an isomeric mixture, the NTP studies tested a commercial TCPP product containing four isomers commonly found in other commercial mixtures of TCPP: tris(1-chloro-2-propyl) phosphate (TCIPP; CASRN 13674-84-5), bis(2-chloro-1-methylethyl) 2-chloropropyl phosphate (CASRN 76025-08-6), bis(2-chloropropyl) 2-chloroisopropyl phosphate (CASRN 76649-15-5), and tris(2-chloropropyl) phosphate (CASRN 6145-73-9). Following procurement of TCPP, the percent purity of the four isomers was determined prior to conducting hazard characterization studies. (Abstract Abridged).

Toxicity Studies of &lt;i&gt;Trayodashang guggulu&lt;/i&gt;, A Classical Ayurvedic Formulation in Experimental Animals

The present study was undertaken to evaluate the Maximum Tolerated Dose and No Observed Adverse Effect Level of Trayodashang guggulu (TG), an Ayurvedic classical formulation, in Wistar rats. TG was administered orally to Wistar rats in as single dose (2000 mg/kg body weight) in an acute toxicity study. Ninety days repeated dose oral toxicity (subchronic) study was carried out by using three dose levels (250, 500 and 1000 mg/kg body weight) administered orally daily for 90 consecutive days and derived from 28 days dose range-finding study. In acute and subchronic toxicity studies, animals were observed for general clinical signs, mortality, weekly body weight changes, weekly feed intake, weekly water intake, blood biochemical investigation, haematological parameters, and gross pathological and histological investigations. In an acute toxicity study, the dose level of 2000 mg/kg of TG was found to be safe when given at a single dose. In the dose rangefinding study and subchronic toxicity study TG was found to be safe at all tested dose levels. No significant changes in food and water consumption, haematological and blood biochemical parameters were noticed at any dose level in both studies. No major changes were noticed during histopathological evaluation in ninety days repeated dose oral toxicity study. The study concluded that the Maximum Tolerated Dose of TG was found at 2000 mg/kg body weight and the No Observed Adverse Effect Level was found at 1000 mg/kg in Wistar rats.

Assessment of Median Lethal Dose and Target Organ Toxicity of Oral Sub-chronic Administration of Newbouldia laevis in Mice and Rat Model of Toxicity

The acute and sub-chronic toxicities of the leaf extract of Newbouldia laevis, an ethnomedicinal herb use in the management of diabetes mellitus was investigated. For the acute toxicity study, 10 – 5000 mg/kg of the extract were administered orally to mice and obvious signs of toxic symptoms and mortality monitored for 24 h post extract administration. In the sub-chronic study, 302 and 604 mg/kg of the extract were orally administered daily for 90 days. Body weight changes as well as haematological and biochemical parameters were determined periodically. Qualitative phytochemistry was also conducted. Presence of flavonoids, saponins, tannins, reducing sugar, steroids, terpenoids, alkaloids and glycosides phytocompounds in the extract were detected. The oral LD50 was estimated to be above 5,000 mg/kg in mice. Ninety days oral administration of ethanol extract of N. laevis produced a significant (P&lt;0.05) reduction in body weight at 604 mg/kg on the 31st day and at both 302 and 604 mg/kg on the 61st and 91st days compared to 5% Tween 20 vehicle control group. For liver function enzymes, the extract at both doses (302 and 604 mg/kg) produced significant (P&lt;0.05) reduction in serum ALT enzyme activity at the 91st day with non-significant reduction in other liver function enzymes compared to vehicle control group. Non-significant changes were also recorded for haematological and kidney function markers. The results from this study provide evidence for safety profile of the ethanol leaves extract of N. laevis thus supportive of its validity in the use for treatment of chronic diseases like diabetes.

Scientific opinion on the tolerable upper intake level for vitamin B6.

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver a scientific opinion on the tolerable upper intake level (UL) for vitamin B6. Systematic reviews of the literature were conducted by a contractor. The relationship between excess vitamin B6 intakes and the development of peripheral neuropathy is well established and is the critical effect on which the UL is based. A lowest-observed-effect-level (LOAEL) could not be established based on human data. A reference point (RP) of 50 mg/day is identified by the Panel from a case-control study, supported by data from case reports and vigilance data. An uncertainty factor (UF) of 4 is applied to the RP to account for the inverse relationship between dose and time to onset of symptoms and the limited data available. The latter covers uncertainties as to the level of intake that would represent a LOAEL. This leads to a UL of 12.5 mg/day. From a subchronic study in Beagle dogs, a LOAEL of 50 mg/kg body weight (bw) per day can be identified. Using an UF of 300, and a default bw of 70 kg, a UL of 11.7 mg/day can be calculated. From the midpoint of the range of these two ULs and rounding down, a UL of 12 mg/day is established by the Panel for vitamin B6 for adults (including pregnant and lactating women). ULs for infants and children are derived from the UL foradults using allometric scaling: 2.2-2.5 mg/day (4-11 months), 3.2-4.5 mg/day (1-6 years), 6.1-10.7 mg/day (7-17 years). Based on available intake data, EU populations are unlikely to exceed ULs, except for regular users of food supplements containing high doses of vitamin B6.

Magnesium Supplementation Alleviates the Toxic Effects of Silica Nanoparticles on the Kidneys, Liver, and Adrenal Glands in Rats.

Concerns regarding the possible hazards to human health have been raised by the growing usage of silica nanoparticles (SiNPs) in a variety of applications, including industrial, agricultural, and medical applications. This in vivo subchronic study was conducted to assess the following: (1) the toxicity of orally administered SiNPs on the liver, kidneys, and adrenal glands; (2) the relationship between SiNPs exposure and oxidative stress; and (3) the role of magnesium in mitigating these toxic effects. A total of 24 Sprague Dawley male adult rats were divided equally into four groups, as follows: control group, magnesium (Mg) group (50 mg/kg/d), SiNPs group (100 mg/kg/d), and SiNPs+ Mg group. Rats were treated with SiNPs by oral gavage for 90 days. The liver transaminases, serum creatinine, and cortisol levels were evaluated. The tissue malondialdehyde (MDA) and reduced glutathione (GSH) levels were measured. Additionally, the weight of the organs and the histopathological changes were examined. Our results demonstrated that SiNPs exposure caused increased weight in the kidneys and adrenal glands. Exposure to SiNPs was also associated with significant alterations in liver transaminases, serum creatinine, cortisol, MDA, and GSH. Additionally, histopathological changes were significantly reported in the liver, kidneys, and adrenal glands of SiNPs-treated rats. Notably, when we compared the control group with the treated groups with SiNPs and Mg, the results revealed that magnesium could mitigate SiNPs-induced biochemical and histopathologic changes, confirming its effective role as an antioxidant that reduced the accumulation of SiNPs in tissues, and that it returns the levels of liver transaminases, serum creatinine, cortisol, MDA, and GSH to almost normal values.

Effects of Multiwall Carbon Nanotubes on Premature Kidney Aging: Biochemical and Histological Analysis.

Carbon nanotubes (CNTs) have gained much attention due to their superb properties, which make them promising options for the reinforcing composite materials with desirable mechanical properties. However, little is known about the linkage between lung exposure to nanomaterials and kidney disease. In this study, we compared the effects on the kidneys and aging for two different types of multiwall carbon nanotubes (MWCNTs): pristine MWCNTs (PMWCNTs) and acid-treated MWCNTs (TMWCNTs), with TMWCNTs being the preferred form for use as a composite material due to its superior dispersion properties. We used tracheal instillation and maximum tolerated dose (MTD) for both types of CNTs. MTD was determined as a 10% weight loss dose in a 3-month subchronic study, and the appropriate dosage for 1-year exposure was 0.1 mg/mouse. Serum and kidney samples were analyzed using ELISA, Western blot, and immunohistochemistry after 6 months and 1 year of treatment. PMWCNT-administered mice showed the activation of pathways for inflammation, apoptosis, and insufficient autophagy, as well as decreased serum Klotho levels and increased serum levels of DKK-1, FGF-23, and sclerostin, while TMWCNTs did not. Our study suggests that lung exposure to PMWCNTs can induce premature kidney aging and highlights a possible toxic effect of using MWCNTs on the kidneys in the industrial field, further highlighting that dispersibility can affect the toxicity of the nanotubes.

Integrated Approach for Synthetic Cathinone Drug Prioritization and Risk Assessment: In Silico Approach and Sub-Chronic Studies in Daphnia magna and Tetrahymena thermophila.

Synthetic cathinones (SC) are drugs of abuse that have been reported in wastewaters and rivers raising concern about potential hazards to non-target organisms. In this work, 44 SC were selected for in silico studies, and a group of five emerging SC was prioritized for further in vivo ecotoxicity studies: buphedrone (BPD), 3,4-dimethylmethcathinone (3,4-DMMC), butylone (BTL), 3-methylmethcathinone (3-MMC), and 3,4-methylenedioxypyrovalerone (MDPV). In vivo short-term exposures were performed with the protozoan Tetrahymena thermophila (28 h growth inhibition assay) and the microcrustacean Daphnia magna by checking different indicators of toxicity across life stage (8 days sublethal assay at 10.00 µg L-1). The in silico approaches predicted a higher toxic potential of MDPV and lower toxicity of BTL to the model organisms (green algae, protozoan, daphnia, and fish), regarding the selected SC for the in vivo experiments. The in vivo assays showed protozoan growth inhibition with MDPV > BPD > 3,4-DMMC, whereas no effects were observed for BTL and stimulation of growth was observed for 3-MMC. For daphnia, the responses were dependent on the substance and life stage. Briefly, all five SC interfered with the morphophysiological parameters of juveniles and/or adults. Changes in swimming behavior were observed for BPD and 3,4-DMMC, and reproductive parameters were affected by MDPV. Oxidative stress and changes in enzymatic activities were noted except for 3-MMC. Overall, the in silico data agreed with the in vivo protozoan experiments except for 3-MMC, whereas daphnia in vivo experiments showed that at sublethal concentrations, all selected SC interfered with different endpoints. This study shows the importance to assess SC ecotoxicity as it can distress aquatic species and interfere with food web ecology and ecosystem balance.