Toxic efects of low doses of lead in subacute exposure rat model

Novija istraživanja ukazuju da svaka izloženost olovu, pa čak i veoma niskim dozama može biti štetna. Podaci o toksičnim mehanizmima i efektima olova iz dosadašnjih animalnih i humanih studija se uglavnom zasnivaju na izloženosti visokim dozama, te stoga postoji potreba da se ispitaju mehanizmi toksičnog dejstva i da se utvrde toksični efekti u uslovima produžene izloženosti niskim dozama olova. Imajući navedeno u vidu, cilj ove disertacije bio je da se na modelu subakutne izloženosti pacova ispita uticaj niskih doza olova na različite organe i sisteme organa. Studija je sprovedena na animalnom modelu Wistar pacova koji su podeljeni u 7 grupa po 6 jedinki od kojih je jedna grupa bila kontrolna a 6 ostalih grupa je tretirano tokom 28 dana rastućim dozama olova 0,1; 0,5; 1; 3; 7; 15 mg Pb/kg t.m./dan. Nakon 24 h od poslednje doze, pacovi su žrtvovani na human način a krv i organi su uzeti na dalju analizu. U krvi su određivani hematološki parametri, biohemijski parametri, hormoni, parametri oksidativnog statusa, bioelementi i olovo, dok su organi podvrgnti patohistološkoj analizi i u njima su određivani parametri oksidativnos stausa, bioelementi, olovo i aktivnost enzima acetilholinesteraze. Primena olova u šest niskih rastućih doza omogućila je modelovanje odnosa doza-odgovor i dobijanje Benchmark doza za ispitivane toksične efekte. Rezultati su pokazali da olovo pri niskim dozama, može ispoljiti toksične efekte skoro na svim ispitivanim organima. Dobijeni rezultati daju uvid u distribuciju olova između krvi i tkiva kao i internim dozama olova koje dovode do štetnih efekata. Izmenjeni profil hematoloških i biohemijskih parametara, zajedno sa izmenjenim nivoima bioelemenata, nastalim oksidativnim stresom, izmenjenom aktivnošću acetilholinesteraze i patohistološkom analizom ispitivanih tkiva, ukazuju na toksične efekte nakon subakutne oralne ekspozicije olovu. Najveći naučni doprinos ove doktorske disertacije je ispitivanje zavisnosti doza–odgovor za svaki pojedinačni parametar kao i određivanje Benchmark doze, koja će dalje doprineti sigurnijoj proceni rizika po zdravlje ljudi pri izloženosti niskim dozama olova. Najniža Benchmark doza dobijena u studiji je za efekat smanjenja nivoa testosterona u serumu pacova što predstavlja kritični toksični efekat studije. Sledeći efekti jesu inhibicija SOD u bubrezima, povećanje nivoa Cu u femuru, sniženje Cu u krvi i povećanje MDA u srcu, a zatim, povećanje TOS u mozgu, povećanje Zn u pankreasu i sniženje Cu u jetri.Recent research indicates that exposure to very low lead doses can be harmful. Data on the toxic mechanisms and effects of lead from previous animal and human studies are mainly based on exposure to high doses, and therefore there is a need to investigate the toxic mechanism and to determine toxic effects under conditions of prolonged exposure to low lead doses. Having this in mind, the aim of this dissertation was to examine the effects of low lead doses on various organs and organ systems in a subacute exposure rat model. The study was conducted on an animal model of Wistar rat. The rats were divided into 7 groups, with 6 rats in each, where one of the them was a control group. The rats from 6 other groups were treated for 28 days with increasing doses of 0.1; 0.5; 1; 3; 7; 15 mg Pb /kg b.w./day. After 24 hours from the last dose, rats were sacrificed and blood and organs were taken away for further analysis. Haematological parameters, biochemical parameters, hormones, oxidative status parameters, bioelements, and lead were determined in the blood, while the organs were subjected to pathohistological analysis and determination of oxidative status parameters, bioelements, lead and acetylcholinesterase enzyme activity. The use of lead in six low-increasing doses enable the modelling of the dose-response relationship and the obtaining of the Benchmark dose for the tested toxic effects. The results showed that lead at low doses can have toxic effects on almost all examined organs. The obtained results provide insight into the distribution of the lead between blood and tissues as well as the internal doses of lead that lead to harmful effects. Altered profiles of hematological and biochemical parameters, together with altered levels of bioelements, oxidative stress, altered acetylcholinesterase activity, and pathohistological analysis of examined tissues, indicate adverse effects after subacute lead exposure. The greatest scientific contribution of this doctoral dissertation is the examination of dose-response relationships for each individual parameter as well as the determination of the Benchmark dose, which will further contribute to a safer assessment of human health risk of low lead dose exposure. The lowest Benchmark dose obtained in the study was for the effect of reducing testosterone levels in rat serum, which is a critical toxic effect of the study. The next determined effects are inhibition of SOD in the kidneys, increased levels of Cu in the femur, decreased Cu in the blood and increased MDA levels in the heart, then, an increase in TOS in the brain, an increase in Zn in the pancreas and a decrease in Cu in the liver

Toxic efects of low doses of lead in subacute exposure rat model

Novija istraživanja ukazuju da svaka izloženost olovu, pa čak i veoma niskim dozama možebiti štetna. Podaci o toksičnim mehanizmima i efektima olova iz dosadašnjih animalnih i humanihstudija se uglavnom zasnivaju na izloženosti visokim dozama, te stoga postoji potreba da se ispitajumehanizmi toksičnog dejstva i da se utvrde toksični efekti u uslovima produžene izloženosti niskimdozama olova. Imajući navedeno u vidu, cilj ove disertacije bio je da se na modelu subakutneizloženosti pacova ispita uticaj niskih doza olova na različite organe i sisteme organa.Studija je sprovedena na animalnom modelu Wistar pacova koji su podeljeni u 7 grupa po 6jedinki od kojih je jedna grupa bila kontrolna a 6 ostalih grupa je tretirano tokom 28 dana rastućimdozama olova 0,1; 0,5; 1; 3; 7; 15 mg Pb/kg t.m./dan. Nakon 24 h od poslednje doze, pacovi sužrtvovani na human način a krv i organi su uzeti na dalju analizu. U krvi su određivani hematološkiparametri, biohemijski parametri, hormoni, parametri oksidativnog statusa, bioelementi i olovo, doksu organi podvrgnti patohistološkoj analizi i u njima su određivani parametri oksidativnos stausa,bioelementi, olovo i aktivnost enzima acetilholinesteraze. Primena olova u šest niskih rastućih dozaomogućila je modelovanje odnosa doza-odgovor i dobijanje Benchmark doza za ispitivane toksičneefekte.Rezultati su pokazali da olovo pri niskim dozama, može ispoljiti toksične efekte skoro na svimispitivanim organima. Dobijeni rezultati daju uvid u distribuciju olova između krvi i tkiva kao iinternim dozama olova koje dovode do štetnih efekata. Izmenjeni profil hematoloških i biohemijskihparametara, zajedno sa izmenjenim nivoima bioelemenata, nastalim oksidativnim stresom,izmenjenom aktivnošću acetilholinesteraze i patohistološkom analizom ispitivanih tkiva, ukazuju natoksične efekte nakon subakutne oralne ekspozicije olovu. Najveći naučni doprinos ove doktorskedisertacije je ispitivanje zavisnosti doza–odgovor za svaki pojedinačni parametar kao i određivanjeBenchmark doze, koja će dalje doprineti sigurnijoj proceni rizika po zdravlje ljudi pri izloženostiniskim dozama olova. Najniža Benchmark doza dobijena u studiji je za efekat smanjenja nivoatestosterona u serumu pacova što predstavlja kritični toksični efekat studije. Sledeći efekti jesuinhibicija SOD u bubrezima, povećanje nivoa Cu u femuru, sniženje Cu u krvi i povećanje MDA usrcu, a zatim, povećanje TOS u mozgu, povećanje Zn u pankreasu i sniženje Cu u jetri.Recent research indicates that exposure to very low lead doses can be harmful. Data on thetoxic mechanisms and effects of lead from previous animal and human studies are mainly based onexposure to high doses, and therefore there is a need to investigate the toxic mechanism and todetermine toxic effects under conditions of prolonged exposure to low lead doses. Having this inmind, the aim of this dissertation was to examine the effects of low lead doses on various organs andorgan systems in a subacute exposure rat model.The study was conducted on an animal model of Wistar rat. The rats were divided into 7groups, with 6 rats in each, where one of the them was a control group. The rats from 6 other groupswere treated for 28 days with increasing doses of 0.1; 0.5; 1; 3; 7; 15 mg Pb /kg b.w./day. After 24hours from the last dose, rats were sacrificed and blood and organs were taken away for furtheranalysis. Haematological parameters, biochemical parameters, hormones, oxidative statusparameters, bioelements, and lead were determined in the blood, while the organs were subjected topathohistological analysis and determination of oxidative status parameters, bioelements, lead andacetylcholinesterase enzyme activity. The use of lead in six low-increasing doses enable themodelling of the dose-response relationship and the obtaining of the Benchmark dose for the testedtoxic effects.The results showed that lead at low doses can have toxic effects on almost all examinedorgans. The obtained results provide insight into the distribution of the lead between blood and tissuesas well as the internal doses of lead that lead to harmful effects. Altered profiles of hematological andbiochemical parameters, together with altered levels of bioelements, oxidative stress, alteredacetylcholinesterase activity, and pathohistological analysis of examined tissues, indicate adverseeffects after subacute lead exposure. The greatest scientific contribution of this doctoral dissertationis the examination of dose-response relationships for each individual parameter as well as thedetermination of the Benchmark dose, which will further contribute to a safer assessment of humanhealth risk of low lead dose exposure. The lowest Benchmark dose obtained in the study was for theeffect of reducing testosterone levels in rat serum, which is a critical toxic effect of the study. Thenext determined effects are inhibition of SOD in the kidneys, increased levels of Cu in the femur,decreased Cu in the blood and increased MDA levels in the heart, then, an increase in TOS in thebrain, an increase in Zn in the pancreas and a decrease in Cu in the liver

Utjecaj adulteranata u mokraći na nalaze komercijalnih testnih traka za otkrivanje zloporabe droga

Immunochromatographic strips for urine drug screening tests (UDSTs) are common and very suitable for drug abuse monitoring, but are also highly susceptible to adulterants kept in the household, which can significantly alter test results. The aim of this study was to see how some of these common adulterants affect UDST results in practice and whether they can be detected by sample validity tests with pH and URIT 11G test strips. To this end we added household chemicals (acids, alkalis, oxidizing agents, surfactants, and miscellaneous substances) to urine samples positive for amphetamine, 3,4-methylenedioxymethamphetamine (MDMA), tetrahydrocannabinol, heroin, cocaine, or benzodiazepines (diazepam or alprazolam) and tested them with one-component immunochromatographic UDST strips. The UDST for cocaine resisted adulteration the most, while the cannabis test produced the most false negative results. The most potent adulterant that barely changed the physiological properties of urine specimens and therefore escaped adulteration detection was vinegar. Besides lemon juice, it produced the most false negative test results. In conclusion, some urine adulterants, such as vinegar, could pass urine specimen validity test and remain undetected by laboratory testing. Our findings raise concern about this issue of preventing urine tampering and call for better control at sampling, privacy concerns notwithstanding, and better sample validity tests.Preliminarna analiza prisutnosti psihoaktivnih tvari u mokraći pomoću imunokromatografskih testnih traka (UDST) našla je primjenu u mnogim područjima. Iako vrlo prikladne u kontroli zloporabe droga, testne su trake iznimno osjetljive na sredstva za patvorenje (adulterante) kao što su kućne kemikalije, što može značajno promijeniti rezultate testa. Cilj ovoga istraživanja bio je ispitati potencijal uobičajeno korištenih adulteranata kada je riječ o utjecaju na rezultate probira na prisutnost psihoaktivnih tvari u mokraći uporabom UDST-a. Ispitivane kemikalije (kiseline, lužine, oksidirajuća sredstva, površinski aktivne tvari i druge) dodane su uzorcima urina u kojima je, tekućinskom kromatografijom – masenom spektrometrijom (LC-MS) prethodno potvrđena prisutnost amfetamina, 3,4-metilendioksimetamfetaina (MDMA), tetrahidrokanabinola, heroina i kokaina benzodiazepina (diazepam ili alprazolam). U ispitivanju su korištene jednokomponentne imunokromatografske testne trake. Manipulacija uzorcima urina provjeravala se pomoću pH traka, kao i biokemijskih testnih traka za semikvantitativno određivanje koncentracija endogenih tvari i specifične težine uzoraka urina pomoću testnih traka URIT 11G. Rezultati ovoga ispitivanja pokazali su da je test za detekciju kokaina u urinu najmanje osjetljiv na utjecaj ispitivanih adulteranata, a test za detekciju kanabinoida najosjetljiviji, posebice u pogledu lažno negativnih rezultata. Najsnažniji adulterant koji je utjecao na rezultate testa a nije promijenio fiziološke parametre urina je alkoholni ocat. Osim soka od limuna, alkoholni ocat dodan u urin proizveo je najveći broj negativnih ishoda testiranja. Može se zaključiti da značajan broj adulteranata utječe na rezultate testa i da je moguće da neki od njih, poput alkoholnoga octa, mogu proći neopaženo pri kontroli valjanosti uzorka. Ovi nalazi upozoravaju na važnost strogo kontroliranog okruženja za uzorkovanje urina kako bi se spriječile manipulacije

Određivanje nivoa hroma, kobalta i nikla u krvi odraslog stanovništva na teritoriji Beograda

The microelements chromium, cobalt and nickel are necessary for the proper functioning of the organism. At higher concentrations, they can cause toxic effects (organ disfunction, genetic damage). They are widespread in the enviroment. They reach our body through food, water, air and/or skin. The aim of this study was to determine the reference values of chromium, cobalt and nickel in the blood of adult residents of Belgrade and determine the degree of influence of individual, socioeconomic factors and lifestyle habits on blood levels of these metals. The study population consisted of adults, healthy population, 18 to 65 years of age, who were voluntary blood donors. The study included 715 men (72.7%) and 269 women (27.3%). Blood collected in vacutainers with heparin, was used for analysis. 984 samples were analysed. The metals were determined using inductively coupled plasma mass spectrometry (7700x, Agilent, USA), with octopol reactive system and micro-flow nebulizer. The average age of participants was 37.2 10.8. The reference values of the analysed metals, shown as the 95 percentile, were 0.95µg/L, 0.62µg/L and 1.46µg/L for chromium, cobalt and nickel, respectively, and were in good correlation with the values obtained in biomonitoring studies conducted in Europe. This study showed that population of Serbian origin had significantly lower blood concentrations of chromium, that cobalt blood levels in women were significantly higher and cobalt and nickel levels increased with age in both sexes. Education and economic status, cigarette smoking and sports did not significantly affect the levels of these metals in the blood.Mikroelementi hrom, kobalt i nikl su potrebni za pravilno funkcionisanje organizma. U većim koncentracijama mogu ispoljiti toksične efekte poput ometanja pravilne funkcije organa i dovesti do genetskih oštećenja i karcinogeneze. Široko su rasprostranjeni u životnoj sredini. Putem hrane, vode, vazduha i/ili kože dospevaju u naš organizam. Cilj rada bio je da se utvrde referentne vrednosti hroma, kobalta i nikla u krvi odraslih stanovnika grada Beograda, kao i stepen uticaja individualnih, socioekonomskih faktora i životnih navika na nivoe ovih metala u krvi. Ispitivanu populaciju je činilo odraslo, zdravo stanovništvo,ukupno 715 muškaraca (72,7%) i 269 žena (27,3%) od 18 do 65 godina starosti, koji su bili dobrovoljni davaoci krvi. Za analizu je korišćena krv sakupljana u vakutejnere sa heparinom. Analizirano je 984 uzoraka. Koncentracija metala je određena metodom masene spektrometrije sa induktivno spregnutom plazmom (7700x, Agilent, USA), sa oktopol reaktivnim sistemom i „micro‐flow“ raspršivačem. Prosečna starost ispitanika iznosila je 37,210,8 godina. Referentne vrednosti ispitivanih metala u krvi, prikazane kao 95. percentil su 0,95 µg/L, 0,62 µg/L i 1,46 µg/L za hrom, kobalt i nikl, redom, su u dobroj korelaciji sa vrednostima dobijenim u biomonitoring studijama sprovedenim u Evropi. Istraživanje uticaja individualnih faktora je pokazalo da je hrom izmeren u značajno nižim koncentracijama kod stanovništva srpske nacionalnosti, da su nivoi kobalta u krvi žena značajno viši i da se nivoi kobalta i nikla povećavaju sa starenjem kod oba pola. Obrazovanje i ekonomski status, pušenje cigareta i bavljenje sportom ne utiču statistički značajno na nivoe ovih metala u krvi.VIII Kongres farmaceuta Srbije sa međunarodnim učešćem, 12-15.10.2022. Beogra

The Role of Persistent Organic Pollutants in Obesity: A Review of Laboratory and Epidemiological Studies

Persistent organic pollutants (POPs) are considered as potential obesogens that may affect adipose tissue development and functioning, thus promoting obesity. However, various POPs may have different mechanisms of action. The objective of the present review is to discuss the key mechanisms linking exposure to POPs to adipose tissue dysfunction and obesity. Laboratory data clearly demonstrate that the mechanisms associated with the interference of exposure to POPs with obesity include: (a) dysregulation of adipogenesis regulators (PPAR and C/EBP); (b) affinity and binding to nuclear receptors; (c) epigenetic effects; and/or (d) proinflammatory activity. Although in vivo data are generally corroborative of the in vitro results, studies in living organisms have shown that the impact of POPs on adipogenesis is affected by biological factors such as sex, age, and period of exposure. Epidemiological data demonstrate a significant association between exposure to POPs and obesity and obesity-associated metabolic disturbances (e.g., type 2 diabetes mellitus and metabolic syndrome), although the existing data are considered insufficient. In conclusion, both laboratory and epidemiological data underline the significant role of POPs as environmental obesogens. However, further studies are required to better characterize both the mechanisms and the dose/concentration-response effects of exposure to POPs in the development of obesity and other metabolic diseases

Exploring the relationship between blood toxic metal(oid)s and serum insulin levels through benchmark modelling of human data: Possible role of arsenic as a metabolic disruptor

The major goal of this study was to estimate the correlations and dose-response pattern between the measured blood toxic metals (cadmium (Cd), mercury (Hg), chromium (Cr), nickel (Ni))/metalloid (arsenic (As)) and serum insulin level by conducting Benchmark dose (BMD) analysis of human data. The study involved 435 non-occupationally exposed individuals (217 men and 218 women). The samples were collected at health care institutions in Belgrade, Serbia, from January 2019 to May 2021. Blood sample preparation was conducted by microwave digestion. Cd was measured by graphite furnace atomic absorption spectrophotometry (GF-AAS), while inductively coupled plasma-mass spectrometry (ICP-MS) was used to measure Hg, Ni, Cr and As. BMD analysis of insulin levels represented as quantal data was done using the PROAST software version 70.1 (model averaging methodology, BMD response: 10%). In the male population, there was no correlation between toxic metal/metalloid concentrations and insulin level. However, in the female population/whole population, a high positive correlation for As and Hg, and a strong negative correlation for Ni and measured serum insulin level was established. BMD modelling revealed quantitative associations between blood toxic metal/metalloid concentrations and serum insulin levels. All the estimated BMD intervals were wide except the one for As, reflecting a high degree of confidence in the estimations and possible role of As as a metabolic disruptor. These results indicate that, in the case of As blood concentrations, even values higher than BMD (BMDL): 3.27 (1.26) (male population), 2.79 (0.771) (female population), or 1.18 (2.96) μg/L (whole population) might contribute to a 10% higher risk of insulin level alterations, meaning 10% higher risk of blood insulin increasing from within reference range to above reference range. The obtained results contribute to the current body of knowledge on the use of BMD modelling for analysing human data

The Role of Persistent Organic Pollutants in Obesity: A Review of Laboratory and Epidemiological Studies

Persistent organic pollutants (POPs) are considered as potential obesogens that may affect adipose tissue development and functioning, thus promoting obesity. However, various POPs may have different mechanisms of action. The objective of the present review is to discuss the key mechanisms linking exposure to POPs to adipose tissue dysfunction and obesity. Laboratory data clearly demonstrate that the mechanisms associated with the interference of exposure to POPs with obesity include: (a) dysregulation of adipogenesis regulators (PPARγ and C/EBPα); (b) affinity and binding to nuclear receptors; (c) epigenetic effects; and/or (d) proinflammatory activity. Although in vivo data are generally corroborative of the in vitro results, studies in living organisms have shown that the impact of POPs on adipogenesis is affected by biological factors such as sex, age, and period of exposure. Epidemiological data demonstrate a significant association between exposure to POPs and obesity and obesity-associated metabolic disturbances (e.g., type 2 diabetes mellitus and metabolic syndrome), although the existing data are considered insufficient. In conclusion, both laboratory and epidemiological data underline the significant role of POPs as environmental obesogens. However, further studies are required to better characterize both the mechanisms and the dose/concentration-response effects of exposure to POPs in the development of obesity and other metabolic diseases.publishedVersio

Exploring the endocrine disrupting potential of lead through benchmark modelling – Study in humans

Exposure to low levels of a toxic metal lead (Pb) affects human health, and its effect as an endocrine disruptor has been reported. However, the precise role of Pb in endocrine health is still unclear because no dose-response relationship has been established for such an effect. The present study aimed to examine blood Pb levels (BLLs) in relation to serum levels of free triiodothyronine (fT3), free thyroxine (fT4), thyroid stimulating hormone (TSH), and insulin in 435 nonoccupationally exposed Serbian subjects (218 women, 217 men, 18–94 years of age, mean age 48). In addition, benchmark dose (BMD) values were calculated for these endocrine endpoints using the PROAST 70.1 software. An explicit dose-response dependency between BLL and TSH, fT3, fT4, testosterone, and insulin serum levels was evident from BMD modelling. The results support the positive association between BLLs and serum insulin levels, with observed dose-response and calculated BMD values of 1.49 and 0.74 μg Pb/dL in males and females, respectively. Collectively, our findings reported potential endocrine-disrupting effects of Pb at the environmental exposure levels experienced by current Serbian population. They also strengthen the notion that the blood Pb threshold level for an endocrine effect is low

Toxic Effects of the Mixture of Phthalates and Bisphenol A-Subacute Oral Toxicity Study in Wistar Rats

Phthalates and bisphenol A, classified as endocrine disruptors, have weak estrogenic, anti-androgenic properties, and aect thyroid hormone regulation. The aim of this study on male rats was to compare the subacute toxic effects of low doses of single compounds (bis (2 –ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), and bisphenol A (BPA)) with the effects of their mixture through dierent biochemical, hormonal, and hematological parameters. Rats were divided into five experimental groups: Control (corn oil), DEHP (50 mg/kg b.w./day), DBP (50 mg/kg b.w./day), BPA (25 mg/kg b.w./day), and MIX (50 mg/kg b.w./day DEHP + 50 mg/kg b.w/day DBP + 25 mg/kg b.w./day BPA). Animals were sacrificed after 28 days of oral treatment and blood was collected for further analysis. The results demonstrated that the mixture produced significant changes in lipid profile, liver-related biochemical parameters, and glucose level. Furthermore, the opposite effects of single substances on the thyroxine level have been shown in comparison with the mixture, as well as a more pronounced effect of the mixture on testosterone level. This study contributes to the body of knowledge on the toxicology of mixtures and gives one more evidence of the paramount importance of mixture toxicity studies, especially in assessing the endocrine disruptive effects of chemicals

Benchmark dose approach in investigating the relationship between blood metal levels and reproductive hormones: Data set from human study

The main objective of this research was to conduct a dose–response modeling between the internal dose of measured blood Cd, As, Hg, Ni, and Cr and hormonal response of serum testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH). The study included 207 male participants from subjects of 5 different cohorts (patients with prostate, testicular, and pancreatic cancer, patients suffering from various thyroid and metabolic disorders, as well as healthy volunteers), enrolled from January 2019 to May 2021 at the Clinical Centre of Serbia in Belgrade, Serbia. Benchmark dose–response modeling analysis was performed with the PROAST software version 70.1, showing the hormone levels as quantal data. The averaging technique was applied to compute the Benchmark dose (BMD) interval (BMDI), with benchmark response set at 10%. Dose-response relationships between metal/metalloid blood concentration and serum hormone levels were confirmed for all the investigated metals/metalloid and hormones. The narrowest BMDI was found for Cd-testosterone and Hg-LH pairs, indicative of high confidence in these estimates. Although further research is needed, the observed findings demonstrate that the BMD approach may prove to be significant in the dose–response modeling of human data