Polimorfizmi gena metalotioneina 2A u ljudi i njihova povezanost s bolestima i razinama elemenata u tragu

Human metallothioneins are a superfamily of low molecular weight intracellular proteins, whose synthesis can be induced by essential elements (primarily Zn and Cu), toxic elements and chemical agents, and stress-producing conditions. Of the four known isoforms in the human body MT2 is the most common. The expression of metallothioneins is encoded by a multigene family of linked genes and can be influenced by single nucleotide polymorphisms (SNPs) in these genes. To date, 24 SNPs in the MT2A gene have been identified with the incidence of about 1 % in various population groups, and three of them were shown to affect physiological and pathophysiological processes. This review summarises current knowledge about these three SNPs in the MT2A gene and their associations with element concentrations in the body of healthy and diseased persons. The most investigated SNP is rs28366003 (MT2A −5 A/G). Reports associate it with longevity, cancer (breast, prostate, laryngeal, and in paranasal sinuses), and chronic renal disease. The second most investigated SNP, rs10636 (MT2A +838G/C), is associated with breast cancer, cardiovascular disease, and type 2 diabetes. Both are also associated with several metal/metalloid concentrations in the organism. The third SNP, rs1610216 (MT2A −209A/G), has been studied for association with type 2 diabetes, cardiomyopathy, hyperglycaemia, and Zn concentrations. Metallothionein concentrations and MT2A polymorphisms have a potential to be used as biomarkers of metal exposure and clinical markers of a number of chronic diseases. This potential needs to be studied and verified in a large number of well-defined groups of participants (several hundreds and thousands) with a focus on particular physiological or pathological condition and taking into consideration other contributing factors, such as environmental exposure and individual genetic and epigenetic makeup.Metalotioneini u ljudskom organizmu povezana su skupina niskomolekularnih unutarstaničnih proteina, čiju sintezu mogu pobuditi esencijalni elementi, ponajprije Zn i Cu, toksični elementi i druge kemijske tvari te razni uvjeti koji izazivaju stres u organizmu. Od četiriju poznatih izoformi metalotioneina u ljudskome tijelu, najčešći oblik je MT2. Izražaj metalotioneina kodira skupina povezanih gena i na to mogu utjecati polimorfizmi pojedinačnoga nukleotida u tim genima. Do sada su otkrivena 24 jednonukleotidna polimorfizma u području gena MT2A, s incidencijom od oko 1 % u raznim skupinama stanovništva, a za tri je takva polimorfizma utvrđeno da bi mogli utjecati na fiziološke i patofiziološke procese. U preglednom radu prikazane su dosadašnje spoznaje o trima jednonukleotidnim polimorfizmima u genu MT2A i njihove povezanosti s koncentracijama elemenata u zdravih i bolesnih osoba. Najviše istraživan jednonukleotidni polimorfizam gena MT2A do sada bio je rs28366003 (MT2A −5A/G) i za njega su pokazane povezanosti s duljinom života, nekoliko tipova karcinoma (u dojki, prostati, grkljanu i sinusima) i s bubrežnim bolestima. Za drugi najviše istraživani polimorfizam rs10636 (MT2A +838G/C) nađene su povezanosti s rakom dojke, bolestima srca i krvnih žila te dijabetesom tipa 2. Za obje te vrste polimorfizama nađene su povezanosti i s koncentracijama metala i polumetala u organizmu. U samo nekoliko istraživanja ispitivana je povezanost polimorfizma rs1610216 (MT2A −209A/G) s dijabetesom tipa 2, kardiomiopatijom, hiperglikemijom i koncentracijama Zn. Podatci u literaturi upućuju na moguću praktičnu primjenu nalaza koncentracija metalotioneina i genskih polimorfizama MT2A kao bioloških pokazatelja izloženosti metalima i kliničkih pokazatelja brojnih kroničnih bolesti. Za tu svrhu potrebna su daljnja opsežna istraživanja u velikom broju dobro definiranih skupina ispitanika (nekoliko stotina i tisuća), usredotočenih na određeno fiziološko ili patološko stanje te uzimajući u obzir druge čimbenike, kao što su okolišna izloženost, osobne životne navike te genetičke i epigenetičke značajke

Određivanje elemenata u kosi metodom ICP-MS: odabir odgovarajuće procedure pranja uzorka

Human hair is a biological sample that is, unlike blood, noninvasively collected and can be used in the assessment of element intake. Before analysis, hair samples need to be washed to eliminate external contamination, for which no standard procedure exists. The present study evaluated the efficiency of different processes for washing hair samples (by non-ionic detergent, acids, solvents, and their mixtures), including ultrasonication before ICP-MS element (As, Ca, Cd, Cu, Fe, Hg, Mg, Mn, Mo, Pb, Se, and Zn) analysis. All tested washing procedures using detergent or solvents were satisfactory, while nitric and hydrochloric acid solutions yielded to “released” and lost elements due to damaged hair (visible discolouration and hair impairment). The application of ultrasonication improved washing efficiency up to 10 %, depending on the tested element and washing procedure. This work is licensed under a Creative Commons Attribution 4.0 International License.Ljudska kosa je biološki uzorak koji se, za razliku od krvi, skuplja neinvazivno i može rabiti u procjeni unosa elemenata. Prije analize uzorke kose potrebno je oprati kako bi se odstranila vanjska onečišćenja za što ne postoje standardni postupci. Istraživanjem je procijenjena učinkovitost različitih postupaka pranja uzoraka kose (neionskim detergentom, kiselinama, otapalima i njihovim mješavinama) uključujući primjenu ultrazvuka prije analize elemenata (As, Ca, Cd, Cu, Fe, Hg, Mg, Mn, Mo, Pb, Se, and Zn) metodom ICP-MS. Ispitivani postupci pranja bili su zadovoljavajući, izuzev primjenom dušične i klorovodične kiseline, pri čemu se elementi “otpuštaju” i gube zbog oštećivanja kose (vidljive su promjena boje i pucanje vlasi). Primjena ultrazvuka pospješila je učinkovitost pranja uzoraka do 10 % ovisno o ispitivanom elementu i postupku pranja. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna

Mercury Disposition in Suckling Rats: Comparative Assessment Following Parenteral Exposure to Thiomersal and Mercuric Chloride

Due to the facts that thiomersal-containing vaccine is still in use in many developing countries, and all forms of mercury have recognised neurotoxic, nephrotoxic, and other toxic effects, studies on disposition of ethylmercury and other mercury forms are still justified, especially at young age. Our investigation aimed at comparing mercury distribution and rate of excretion in the early period of life following exposure to either thiomersal (TM) or mercuric chloride (HgCl2) in suckling rats. Three experimental groups were studied: control, TM, and HgCl2, with 12 to18 pups in each. Both forms of mercury were administered subcutaneously in equimolar quantities (0.81 μmol/kg b.w.) three times during the suckling period (on the days of birth 7, 9, and 11) to mimic the vaccination regimen in infants. After the last administration of TM or HgCl2, total mercury retention and excretion was assessed during following six days. In TM-exposed group mercury retention was higher in the brain, enteral excretion was similar, and urinary excretion was much lower compared to HgCl2-exposed sucklings. More research is still needed to elucidate all aspects of toxicokinetics and most harmful neurotoxic potential of various forms of mercury, especially in the earliest period of life

Pre-amplification as a method for improvement of quantitative RT-PCR analysis of circulating miRNAs

Introduction: The assessment of circulating miRNAs is challenging and still limited due to their low concentrations, small size and lack of reference values in human biological samples. Pre-amplification of complementary DNAs may facilitate reliable miRNA quantification. The aim of our study was to evaluate the efficacy of pre-amplification as a step to increase the sensitivity of qPCR analysis for five candidate circulating miRNAs presumably related to toxic metals and cigarette smoke exposure: miR-1537, miR-190b, miR-16, miR-21, and miR-146a. Materials and methods: Candidate miRNAs expression was analysed in plasma samples of 19 mother-newborn pairs. For isolation, transcription, pre-amplification and qPCR quantification kits and protocols by Qiagen (Hilden, Germany) were used. Paired t-test or Wilcoxon rank test were used to compare miRNAs expression levels with and without a pre-amplification step prior to qPCR, separately in maternal and cord plasma. Intraclass correlation (ICC) was calculated as an agreement measure between procedures for each miRNA. Results: Pre-amplification facilitated the detection of all assayed miRNAs with an overall cycle threshold (CT) improvement of 6.6 ± 0.89 (P < 0.05). Excellent ICCs (> 0.90) were found between data for preamplified and not preamplified miR-16, miR-21 and miR-146a. However, these correlations for low expressed miR-190b were moderate (0.79 in maternal; 0.61 in cord plasma) and poor for miR-1537 (0.49 in maternal; no correlation in cord plasma). Conclusion: Pre-amplification is a useful, necessary step in the analysis of miR-1537 and miR-190b as a reliable procedure facilitating extracellular miRNA expression detection in human plasma by real-time PCR quantification

Kadmij i olovo u uzorcima vučje jetre: optimizacija metode razgradnje uzoraka uz pomoć mikrovalova

A microwave-assisted digestion method for the determination of cadmium (Cd) and lead (Pb) by inductively coupled plasma mass spectrometry (ICP-MS) was optimised on certified reference material (CRM) (bovine liver, BCR-185R) and wolf liver samples. Different factors influencing digestion efficiency (temperature, time, composition of the digestion mixture, sample mass) were tested. Validation included linearity (up to 200 μg L-1 for Cd and Pb), detection (0.003 μg L-1 for Cd and 0.035 μg L-1 for Pb), and quantification (0.008 μg L-1 for Cd and 0.081 μg L-1 for Pb) limits. Good agreement between measured and certified values was achieved in all conditions, with recoveries ranging from 94 % to 111 % for Cd and from 95 % to 105 % for Pb. The precision of the method, expressed as relative standard deviation, was up to 3 % for Cd and 8 % for Pb. The best digestion parameters (260 °C, 30 min, 1 mL HNO3+4 mL H2O, 0.1 g of CRM) based on accuracy and precision were applied on two wolf liver samples to evaluate the need for the predigestion step (freeze-drying) and appropriate mass of the sample. Freeze-drying improved precision and minimising the tissue mass to 0.1 g reduced the matrix effect. Using these optimised digestion conditions, we determined Cd and Pb in 40 wolf livers collected in Croatia, and their medians (0.055 μg g-1 and 0.107 μg g-1, respectively) were in the range of previously reported data for the grey wolf.Certifi cirani referenti materijal (CRM) govedskih jetara (BCR-185R) i uzorci vučjih jetara koristili su se za optimizaciju metode razgradnje uzoraka prije mjerenja kadmija (Cd) i olova (Pb) masenom spektrometrijom induktivno spregnute plazme (ICP-MS). Ispitivani su različiti uvjeti koji utječu na učinkovitost razgradnje (temperatura, vrijeme, sastav otopine za razgradnju, masa uzorka). Validacijom je obuhvaćeno ispitivanje linearnosti (do 200 μg L-1 Cd/Pb), granice detekcije (0,003 μg L-1 za Cd, 0.035 μg L-1 za Pb) i kvantifikacije (0,008 μg L-1 za Cd, 0,081 μg L-1 za Pb). Postignuto je dobro slaganje izmjerenih i certificiranih vrijednosti u svim ispitivanim uvjetima uz izračunati raspon iskorištenja 94 % do 111 % za Cd i 95 % do 105 % za Pb. Najveća relativna standardna devijacija, kao mjera preciznosti, iznosila je 3 % za Cd i 8 % za Pb. Najbolji uvjeti za razgradnju (260 °C, 30 min, 1 mL HNO3+4 mL H2O, 0,2 g CRM), izabrani prema točnosti i preciznosti, primijenjeni su na uzorke vučjih jetara pri procjeni odgovarajuće mase uzorka i potrebe za uvođenjem dodatnog koraka prije razgradnje (liofilizacije). Liofilizacija poboljšava preciznost pa je preporučujemo pri pripremi uzoraka tkiva. Također, najmanja masa uzorka izabrana je ne samo zbog bolje preciznosti nego i zbog najmanjeg utjecaja matrice te potrebne količine tkiva. Medijani Cd (0,055 μg g-1) i Pb (0,107 μg g-1 mokre mase) dobiveni analizom 40 uzoraka vučjih jetara skupljenih u Hrvatskoj bili su u rasponu vrijednosti objavljenih u literaturi za sivog vuka

Određivanje kemijskog sastava i antioksidacijskog potencijala plodova jarebike (Sorbus aucuparia L.) porijeklom iz alpsko-dinarskog područja Republike Hrvatske

Research background. The rowan (Sorbus aucuparia L.) is a small tree in the Rosaceae family with characteristic orange-red fruits. The raw fruits can be used for making jams, juices and puree, while the dried fruits are used for teas. In folk medicine, they have been used to prevent scurvy and bleeding or as a diuretic and laxative. The aim of this study is to characterize the proximate chemical composition, antioxidant potential and macro- and trace elements of the rowan fruits for their potential use as a functional food. Experimental approach. The fruits were collected from 12 populations in the Alpine-Dinaric region of Croatia. After collection, the samples were transported to the laboratory, cut into small pieces, placed in plastic containers and stored at -20 °C until analysis. Proximate chemical composition, including ash, water, cellulose, crude fat and crude protein, was determined according to standard methods and total carbohydrates as non-structural carbohydrates. Total phenolic content (TPC) and antioxidant capacity (TAC) were also measured. For multielement analysis, fruits were cleaned from the dust, lyophilised, homogenised and acid-digested in a microwave system. Concentrations of elements were determined using the inductively coupled plasma mass spectrometry. Results and conclusions. The basic constituents in the analysed fruits were (in %): water 76.53, total carbohydrates 17.45, crude proteins 2.98, crude fats 1.49, cellulose 1.07 and ash 1.29. On average, the TPC was 932 mg/100 g and the TAC was (60.1±14.5) % and (4.1±1.2) mmol/100 g, determined by DPPH and FRAP assay, respectively. Mass fractions of elements decreased as follows (in mg/kg): K 2485>Ca 459>P 206, Mg 193>Na 6.29>Fe 3.68>Mn 3.58>Zn 1.11>Cu 0.731>Mo 0.098>Co 0.003>Se 0.001. Compared to the literature, the phenolic and element content of the rowan fruits is similar to that of blueberry and raspberry. The obtained results suggest that rowan fruits have valuable nutritional properties and could be useful for fortification in the food industry. Novelty and scientific contribution. The importance of the obtained results is reflected in filling in the gaps in the literature on the composition of elements, especially on the content of essential macro- and trace elements as well as the antioxidant potential of rowan fruits.Pozadina istraživanja. Jarebika (Sorbus aucuparia L.) je malo stablo iz porodice Rosaceae s karakterističnim narančasto-crvenim plodovima. Od sirovih plodova mogu se pripremati džemovi, sokovi i voćne kaše, a od osušenih čajevi. U narodnoj medicini koristi se za sprječavanje razvoja skorbuta i krvarenja, odnosno kao diuretik i laksativ. Svrha je ovog istraživanja bila odrediti kemijski sastav, antioksidacijski potencijal te udjele mineralnih tvari u plodovima jarebike, radi određivanja mogućnosti njezine upotrebe kao funkcionalne hrane. Eksperimentalni pristup. Plodovi su prikupljeni iz 12 različitih populacija u alpsko-dinarskom području Hrvatske. Uzorci su nakon prikupljanja prevezeni u laboratorij, izrezani na male komadiće, stavljeni u plastične posude i čuvani na -20 °C do daljnjih analiza. Kemijski sastav, uključujući masene udjele pepela, vode, celuloze, masti i proteina, određen je pomoću standardnih metoda, a ukupni ugljikohidrati kao nestrukturni ugljikohidrati. Određeni su i ukupni udjel fenola (TPC) i antioksidacijski potencijal (TAC). Za multielementnu analizu plodovi su očišćeni od prašine, liofilizirani, homogenizirani i razgrađeni u mikrovalnom visokotlačnom reaktoru. Koncentracije elemenata određene su spektrometrijom masa uz induktivno spregnutu plazmu. Rezultati i zaključci. Osnovni sastojci u ispitanim plodovima bili su (u %): voda 76,53; ukupni ugljikohidrati 17,45; proteini 2,98; masti 1,49; celuloza 1,07 i pepeo 1,29. Utvrđen je prosječan udjel TPC od 932 mg/100 g, a DPPH odnosno FRAP metodom TAC od (60,1±14,5) % odnosno (4,1±1,2) mmol/100 g. Maseni udjeli elemenata smanjivali su se prema slijedu (u mg/kg): K 2485>Ca 459>P 206, Mg193>Na 6,29>Fe 3,68>Mn 3,58>Zn 1,11>Cu 0,731>Mo 0,098>Co 0,003>Se 0,001. U usporedbi s literaturom, udjeli fenola i mineralnih tvari u plodovima jarebike bili su slični onima u borovnici i malini. Dobiveni rezultati pokazuju da plodovi jarebike imaju vrijedna hranjiva svojstva i mogu biti koristan dodatak u prehrambenoj industriji. Novina i znanstveni doprinos. Važnost dobivenih rezultata ogleda se u nadopuni literature podacima o sastavu elemenata, naročito udjelu esencijalnih makro i mikroelemenata, kao i antioksidacijskom potencijalu plodova jarebike

In female rats, ethylene glycol treatment elevates protein expression of hepatic and renal oxalate transporter sat-1 (Slc26a1) without inducing hyperoxaluria

Aim To investigate whether the sex-dependent expression of hepatic and renal oxalate transporter sat-1 (Slc26a1) changes in a rat model of ethylene glycol (EG)-induced hyperoxaluria. Methods Rats were given tap water (12 males and 12 females; controls) or EG (12 males and 12 females; 0.75% v/v in tap water) for one month. Oxaluric state was confirmed by biochemical parameters in blood plasma, urine, and tissues. Expression of sat-1 and rate-limiting enzymes of oxalate synthesis, alcohol dehydrogenase 1 (Adh1) and hydroxy-acid oxidase 1 (Hao1), was determined by immunocytochemistry (protein) and/or real time reverse transcription polymerase chain reaction (mRNA). Results EG-treated males had significantly higher (in μmol/L; mean ± standard deviation) plasma (59.7 ± 27.2 vs 12.9 ± 4.1, P < 0.001) and urine (3716 ± 1726 vs 241 ± 204, P < 0.001) oxalate levels, and more abundant oxalate crystaluria than controls, while the liver and kidney sat-1 protein and mRNA expression did not differ significantly between these groups. EG-treated females, in comparison with controls had significantly higher (in μmol/L) serum oxalate levels (18.8 ± 2.9 vs 11.6 ± 4.9, P < 0.001), unchanged urine oxalate levels, low oxalate crystaluria, and significantly higher expression (in relative fluorescence units) of the liver (1.59 ± 0.61 vs 0.56 ± 0.39, P = 0.006) and kidney (1.77 ± 0.42 vs 0.69 ± 0.27, P < 0.001) sat-1 protein, but not mRNA. The mRNA expression of Adh1 was femaledominant and that of Hao1 male-dominant, but both were unaffected by EG treatment. Conclusions An increased expression of hepatic and renal oxalate transporting protein sat-1 in EG-treated female rats could protect from hyperoxaluria and oxalate urolithiasis

The effect of metallothionein 2A gene polymorphism and exposure to cigarette smoke on levels of toxic and essential metals at childbirth and steroid hormones concentrations in the placenta

U zdravih rodilja nakon ročnog rodničkog porođaja procijenjen je utjecaj glavnih izvora izloženosti toksičnim metalima u općoj populaciji, pušenjem cigareta (Cd i Pb) i konzumacijom morske hrane (Hg), te polimorfizma MT2A rs28366003 na koncentracije toksičnih metala (Cd, Pb i Hg) i s njima povezanih esencijalnih elemenata (Fe, Zn, Cu i Se) u krvi majke, posteljici i krvi pupkovine, steroidne hormone u posteljici kao i koncentracije MT2 i slobodnih –SH skupina u serumu majki. Uspoređene su ispitanice iz geografskog područja prebivališta u priobalju s mediteranskom prehranom bogatom ribom (n = 96) s ispitanicama u kontinentalnoj Hrvatskoj (n = 196). Sve analize provedene su najsuvremenijim metodama, dobivene vrijednosti povezane su s podacima o ispitanicama iz anketnog upitnika i rezultati statistički obrađeni. Pušačice u odnosu na nepušačice imale su povećane koncentracije Cd i Pb u krvi majke, posteljici i krvi pupkovine, Fe i Cu u krvi pupkovine i Zn u posteljici te smanjene koncentracije Se u krvi i slobodnih –SH skupina u serumu majke dok je povećanje MT2 u serumu majke bilo je srazmjerno intenzitetu pušenja. Nije bilo promjena koncentracijama hormona progesterona i estradiola u posteljici. U svim biološkim uzorcima koncentracije Hg i Se su pozitivno korelirale s učestalošću konzumacije ribe. Ispitanice iz priobalnog područja imale su veći unos morske hrane (>55 % ispitanica u priobalju konzumiralo je ribu barem 1 puta na tjedan, a u kontinentalnom području rjeđe ili nikada). Ispitanice u priobalju imale su veće koncentracije Fe u krvi pupkovine i Zn u posteljici te Cd i Cu u krvi majke i posteljici. Nije nađen utjecaj polimorfizma jednog nukleotida u genu MT2A c.-77A>G (rs28366003) na koncentracije Cd, Pb ili Hg u krvi majke niti na porođajne mase i duljine. Nepušačice s genotipom AG/GG u odnosu na genotip AA imale su smanjeno Fe u posteljici. Izvoran doprinos rada jesu rezultati koji mogu poslužiti kao temelj za istraživanja utjecaja polimorfizma MT2A na koncentracije toksičnih i esencijalnih elemenata i njihove moguće učinke na zdravlje u žena tijekom reprodukcijskog razdoblja i njihovih potomaka u uvjetima svakodnevne izloženosti iz okoliša. Daljnja istraživanja u osjetljivim skupinama opće populacije u Hrvatskoj, kao što su parovi majke–dijete, trebala bi uključiti veliki broj ispitanika uzimajući u obzir glavne izvore unosa metala.In healthy postpartum women after term vaginal delivery, the combined effects of the main sources of exposure to toxic metals in general population were evaluated, i.e. cigarette smoking (for Cd and Pb) and seafood/fish consumption (for Hg), and maternal gene polymorphism MT2A rs2836600 on the concentrations of the main toxic metals (Cd, Pb and Hg) and essential elements (Fe, Zn, Cu and Se) in maternal blood, placenta and cord blood, on the concentrations of steroid hormones in the placenta, and on concentrations of MT2 and free –SH groups in maternal serum. Study participants from coastal Croatia with a traditional Mediterranean diet rich in fish (n = 96) were compared with subjects from continental Croatia (n = 196). All samples were analysed by state-of-the-art methods, the analytical findings connected with the data on subjects from the questionnaire and all of the results were statistically evaluated. Smokers vs. non-smokers had higher Cd and Pb in maternal blood, cord blood and placenta, Fe and Cu in cord blood and Zn in placenta and lower concentrations of Se in maternal blood and free –SH groups in maternal serum whereas an increase of maternal serum MT2 was related to smoking intensity. No changes were found in hormones progesterone and estradiol in the placenta. In all of the biological samples, the levels of Hg and Se positively correlated with the frequency of fish consumption. Subjects from the coastal area had higher seafood intake (>55 % participants from the coast consumed fish at least once a week, and continental participants less than this or never). They also had higher concentrations of Fe in cord blood, Zn in placenta and Cd and Cu in maternal blood and placenta. No impact of single nucleotide polymorphism MT2A, c.-77A>G (rs28366003) was found on concentrations of Cd, Pb or Hg in maternal blood or birth weight and length. Non-smokers with AG/GG vs. AA genotype had lower concentrations of Fe in placenta. The original contribution of this work are the results that may lay the foundation for studies on the impact of the single nucleotide polymorphism MT2A on toxic and essential element levels and their health effects under conditions of everyday environmental exposure in women during the reproductive period and their offspring. Further studies in vulnerable population groups such as mother–child pairs and in the general Croatian population should include larger numbers of subjects and representative population groups considering main sources of metal intake

Metallothionein 2A

Human metallothioneins are a superfamily of low molecular weight intracellular proteins, whose synthesis can be induced by essential elements (primarily Zn and Cu), toxic elements and chemical agents, and stress-producing conditions. Of the four known isoforms in the human body MT2 is the most common. The expression of metallothioneins is encoded by a multigene family of linked genes and can be influenced by single nucleotide polymorphisms (SNPs) in these genes. To date, 24 SNPs in the MT2A gene have been identified with the incidence of about 1 % in various population groups, and three of them were shown to affect physiological and pathophysiological processes. This review summarises current knowledge about these three SNPs in the MT2A gene and their associations with element concentrations in the body of healthy and diseased persons. The most investigated SNP is rs28366003 (MT2A −5 A/G). Reports associate it with longevity, cancer (breast, prostate, laryngeal, and in paranasal sinuses), and chronic renal disease. The second most investigated SNP, rs10636 (MT2A +838G/C), is associated with breast cancer, cardiovascular disease, and type 2 diabetes. Both are also associated with several metal/metalloid concentrations in the organism. The third SNP, rs1610216 (MT2A −209A/G), has been studied for association with type 2 diabetes, cardiomyopathy, hyperglycaemia, and Zn concentrations. Metallothionein concentrations and MT2A polymorphisms have a potential to be used as biomarkers of metal exposure and clinical markers of a number of chronic diseases. This potential needs to be studied and verified in a large number of well-defined groups of participants (several hundreds and thousands) with a focus on particular physiological or pathological condition and taking into consideration other contributing factors, such as environmental exposure and individual genetic and epigenetic makeup.Metalotioneini u ljudskom organizmu povezana su skupina niskomolekularnih unutarstaničnih proteina, čiju sintezu mogu pobuditi esencijalni elementi, ponajprije Zn i Cu, toksični elementi i druge kemijske tvari te razni uvjeti koji izazivaju stres u organizmu. Od četiriju poznatih izoformi metalotioneina u ljudskome tijelu, najčešći oblik je MT2. Izražaj metalotioneina kodira skupina povezanih gena i na to mogu utjecati polimorfizmi pojedinačnoga nukleotida u tim genima. Do sada su otkrivena 24 jednonukleotidna polimorfizma u području gena MT2A, s incidencijom od oko 1 % u raznim skupinama stanovništva, a za tri je takva polimorfizma utvrđeno da bi mogli utjecati na fiziološke i patofiziološke procese. U preglednom radu prikazane su dosadašnje spoznaje o trima jednonukleotidnim polimorfizmima u genu MT2A i njihove povezanosti s koncentracijama elemenata u zdravih i bolesnih osoba. Najviše istraživan jednonukleotidni polimorfizam gena MT2A do sada bio je rs28366003 (MT2A −5A/G) i za njega su pokazane povezanosti s duljinom života, nekoliko tipova karcinoma (u dojki, prostati, grkljanu i sinusima) i s bubrežnim bolestima. Za drugi najviše istraživani polimorfizam rs10636 (MT2A +838G/C) nađene su povezanosti s rakom dojke, bolestima srca i krvnih žila te dijabetesom tipa 2. Za obje te vrste polimorfizama nađene su povezanosti i s koncentracijama metala i polumetala u organizmu. U samo nekoliko istraživanja ispitivana je povezanost polimorfizma rs1610216 (MT2A −209A/G) s dijabetesom tipa 2, kardiomiopatijom, hiperglikemijom i koncentracijama Zn. Podatci u literaturi upućuju na moguću praktičnu primjenu nalaza koncentracija metalotioneina i genskih polimorfizama MT2A kao bioloških pokazatelja izloženosti metalima i kliničkih pokazatelja brojnih kroničnih bolesti. Za tu svrhu potrebna su daljnja opsežna istraživanja u velikom broju dobro definiranih skupina ispitanika (nekoliko stotina i tisuća), usredotočenih na određeno fiziološko ili patološko stanje te uzimajući u obzir druge čimbenike, kao što su okolišna izloženost, osobne životne navike te genetičke i epigenetičke značajke

Genetic and Epigenetic Features of Uveal Melanoma—An Overview and Clinical Implications

Uveal melanoma (UM) is rare, but it is the most common primary intraocular malignancy among adults. This review represents the molecular, genetic, and immunobiological mechanisms involved in UM carcinogenesis and progression, as well as data about the association of chromosomal changes, genetic mutations, selective proteins, and biochemical biomarkers with the clinical implications of UM. Genetic analysis has the potential to identify patients with a high risk of UM metastasis, enabling management that is more effective and allowing for the follow-up of patients. Advancements in molecular characterization of UM offer opportunities to develop targeted therapeutic strategies by focusing on relevant signaling pathways. Changes in miRNA expression could be useful in the diagnosis and prognosis of UM, due to unique miRNA profiles in melanoma cells or tissue and its association with metastasis. Although liver function tests do not provide enough data on the prognosis of UM, due to the high frequency of liver metastasis, liver function tests (LFTs) might be useful indicators; however, the absence of rising LFT values cannot lead to the exclusion of liver metastases. Molecular analysis of tumor tissue will allow us to identify patients with the added benefit of new therapeutic agents and provide a better insight into melanoma pathogenesis and its biological behavior