Development and characterization of a non-transgenic rat model of tauopathy induced by injection of tau protein into the entorhinal cortex

U istraživanju Alzheimerove bolesti (AD) najviše su korišteni transgenični animalni modeli koji zapravo nisu pogodni za istraživanje složenih procesa sporadične AD, koja čini više od 95% svih slučajeva AD-a. Cilj je ovog istraživanja bio karakterizacija netransgeničnog štakorskog modela tauopatije koji će pridonijeti boljem razumijevanju patologije transsinaptičkog širenja i agregacije tau proteina u AD-u i mogućem iznalaženju novih terapijskih ciljeva za sprječavanje nastanka te zaustavljanje širenja navedenih patoloških promjena. Budući da najranije neurofibrilarne promjene u mozgu osoba s AD-om nastaju u moždanom deblu i entorinalnoj moždanoj kori, odakle se šire duž anatomski povezanih područja, za proučavanje njezinog transsinaptičkog širenja provedena je jednostrana stereotaksijska inokulacija tau oligomera ili sintetskih tau fibrila u medijalni dio entorinalne moždane kore Wistar štakora. Inokulacija tau oligomera i tau fibrila uzrokovala je progresiju neurofibrilarnih promjena iz entorinalne moždane kore u druga, s njom povezana područja mozga, slično kao što se to događa i u mozgu čovjeka s AD-om. Nastanak i širenje patološki promijenjenog tau proteina, kako je pokazano pomoću AT8 protutijela na relativno velik epitop i vjerojatno strukturno važan dio tau proteina fosforiliran na serinu199, serinu202 i treoninu205, događalo se brže u životinja inokuliranih tau fibrilima u odnosu na životinje kojima su bili inokulirani tau oligomeri. U životinja kojima su inokulirani tau oligomeri, zbog sporijeg širenja bilo je potrebno jedanaest mjeseci za zahvaćanje svih područja mozga. Osim navedenih neurofibrilarnih promjena, inokulacija tau fibrila i tau oligomera izazvala je i pojavu konformacijski promijenjenog tau proteina, stvaranje inkluzija pozitivnih na histokemijska bojenja po Gallyasu i Bielschowskom koja su potvrdila akumuliranje fosforiliranih tau proteina, nakupljanje amiloida-β, gubitak sinapsi u hipokampusu i tim promjenama odgovarajuće značajne kognitivne deficite potvrđene testovima otvorenog polja, prepoznavanja novog objekta, prepoznavanja nove lokacije objekta i T-labirint testom.Transgenic mouse models have been extensively used in Alzheimer’s disease (AD) research, although they are limited in their ability to replicate the complex process of sporadic AD, which concerns well over 95% of all AD cases. In this study, we aimed to characterize a non-transgenic rat model of tauopathy that can contribute to a better understanding of possible pathological changes, trans-synaptic spread and tau protein aggregation in AD, and find new therapeutic targets to prevent the onset or stop the spread of those pathological changes. To analyze trans-synaptic spread in Wistar rats, unilateral inoculation of tau oligomers or synthetic tau fibrils into the medial entorhinal cortex was performed, since it has been shown that the earliest neurofibrillary changes in AD brains originate in the brainstem and entorhinal cortex from where they further propagate along anatomically connected regions. Inoculation of tau oligomers and tau fibrils caused the progression of neurofibrillary changes from the entorhinal cortex to other connected brain regions, similar to AD-related changes outlined in the human brain. The development and spreading of supposedly the earliest tau pathological change, as revealed by using the AT8 monoclonal antibody to the relatively complex epitope and likely structurally important part of tau protein phosphorylated at Ser199, Ser202, and Thr205 residues, occurred much faster in animals inoculated with tau fibrils than in animals inoculated with tau oligomers. Due to a slower propagation, in animals inoculated with tau oligomers it took eleven months for all areas of the brain to be affected. In addition to neurofibrillary changes, stereotaxic inoculation of tau fibrils and tau oligomers caused the appearance of conformationally altered tau protein, formation of Gallyas- and Bielschowsy-positive inclusions that confirmed the accumulation of phosphorylated tau proteins, accumulation of amyloid , loss of synapses in the hippocampus, and significant corresponding cognitive deficits documented by using the open field test, novel object location test, novel object recognition test and T-maze test

Otvorenost, ali pod koju cijenu – stavovi i praksa hrvatskih autora

Objavljivanje u otvorenom pristupu (OA, od engl. open access) danas je prevladavajući oblik komunikacije znanstvenih rezultata. Prema rezultatima ranijih istraživanja udio OA u ukupnom broju međunarodno vidljivih radova hrvatskih autora iznosi 74 %. Početkom 2023. godine provedena je anketa među korisnicima liste znanstvenici.hr da bi se ispitali stavovi i praksa hrvatskih autora u svezi s OA. Anketa je imala cilj sagledati razinu podrške objavljivanju u OA, prepoznavanje pozitivnih i negativnih aspekata, motivaciju za objavljivanje u OA, izvore financiranja te razloge sklonosti određenim OA izdavačima. Prikupljeno je 763 potpuno ispunjenih upitnika. Analiza rezultata pokazala je da 75 % ispitanika podržava objavljivanje u OA te prepoznaje prednosti koje to donosi znanstvenom istraživanju i obrazovnom procesu. Više od 80 % ispitanika slaže se da OA doprinosi bržoj distribuciji novih spoznaja te da radovi objavljeni u OA imaju veće čitateljstvo i vidljivost. S druge strane, gotovo trećina ispitanika smatra da OA povećava komercijalizaciju znanstvenog izdavaštva te da rastući broj objava smanjuje kvalitetu recenzentskog postupka. Kad je u pitanju odabir časopisa za objavljivanje, većini ispitanika kojima znanstveni časopisi predstavljaju najvažniji kanal komunikacije važniji su ugled časopisa i odjek u znanstvenoj zajednici nego otvoren pristup. Praksa OA časopisa koji objavljuju isključivo uz naplatu troškova objave izaziva najviše razilaženja u stavovima. Ispitanici s pozitivnim stavom objavljuju u takvim OA časopisima, poglavito zbog brzine recenziranja i objave. S druge strane, oni s negativnim stavom smatraju da je izdavačima OA časopisa koji naplaćuju objavu važnija zarada od kvalitete objavljenih članaka, navode da nemaju sredstva za plaćanje troškova objave ili ih ne žele plaćati jer se protive preprekama koje se postavljaju objavljivanju znanstvenih rezultata

The effect of light therapy on plasma levels of brain-derived neurotrophic factor and serum levels of interleukin-6 in patients with treatment-resistant depression

Depresivni poremećaj je među vodećim poremećajima koji uzrokuju pad kvalitete života, radne i socijalne funkcionalnosti, a oko 30 % oboljelih ima terapijski rezistentni depresivni poremećaj (TRDP). Terapija svjetlom se kao dodatna metoda primjenjuje u liječenju TRDP-a. Do sada nisu ispitivani moždani neurotrofni čimbenik (BDNF) i interleukin-6 (IL-6) kao periferni pokazatelji djelovanja fototerapije. Rezultati istraživanja u koje je bilo uključeno 60 ženskih ispitanika ukazuju da nakon 4 tjedna fototerapije nema značajne promjene u koncentracijama BDNF-a u plazmi i IL-6 u serumu, kao i da poboljšanje depresivnih simptoma nije u korelaciji s promjenama koncentracija BDNF-a i IL-6. Ispitanice koje su prema ocjenskim ljestvicama HAMD-17 i MADRS dobro odgovorile na fototerapiju ili su postigle remisiju, imale su veći porast perifernih koncentracija BDNF-a i IL-6, u odnosu na one koje nisu dobro odgovorile. Istraživanje je pridonijelo boljem razumijevanju djelovanja fototerapije i njene primjene kod TRDP-a, što otvara dodatne mogućnosti za buduće studije.Depressive disorder is among the leading disorders that cause a decline in quality of life, work and social functionality, and about 30 % of patients have treatment-resistant depression (TRD). Light therapy is used as an additional method in the treatment of TRD. So far, brain-derived neurotrophic factor (BDNF) and interleukin-6 (IL-6) have not been investigated as peripheral indicators of the effect of phototherapy. The results of the research involving 60 female subjects indicate that there is no significant change in plasma levels of BDNF and serum levels of IL-6 after 4 weeks of phototherapy, as well as that the improvement of depressive symptoms is not correlated with the changes in levels of BDNF and IL-6. Subjects who, according to the HAMD-17 and MADRS rating scales, responded well to phototherapy or achieved remission, had a greater increase in peripheral levels of BDNF and IL-6 compared to those who did not respond well. The research contributed to a better understanding of the effect of phototherapy and its application in TRD, which opens additional opportunities for future studies

The effect of ganglioside composition on expression, submembrane localization and activity of Na+, K+-ATPase and plasma membrane Ca2+-ATPase in mouse brain

U mišjim modelima s poremećenom sintezom glikosfingolipida gangliozida dolazi do promjene u lipidnom okolišu membrane potrebnom za pravilno funkcioniranje membranskih proteina. Cilj ovog istraživanja bio je višerazinskim metodološkim pristupom sustavno utvrditi utjecaj promijenjenog sastava gangliozida u mišjem modelu St8sia1 null na gensku i proteinsku ekspresiju, te submembransku lokalizaciju pojedinih izoformi i podjedinica Na+, K+-ATPaze (NKA), Ca2+-ATPaze stanične membrane (PMCA) i neuroplastina (Np), kao i na enzimsku aktivnost NKA i PMCA u različitim regijama mozga. Analizom genske ekspresije metodom lančane reakcije polimerazom u stvarnom vremenu utvrđene su promjene u ekspresiji gena za katalitičke i β- podjedinice NKA, izoforme PMCA između moždane kore, maloga mozga i hipokampusa miševa St8sia1 null u odnosu na kontrolnu skupinu, ukazujući na različitu staničnu potrebu za pojedinim izoformama, dok je u sve tri regije mozga utvrđen porast ekspresije gena za neuroplastin. Westernskom metodom otiska pokazano je da dolazi do promjene u količinskom sadržaju istraživanih proteina u regijama mozga St8sia1 null u vidu porasta količine katalitičkih podjedinica NKA te izoforme PMCA2 u moždanoj kori, PMCA4 u malome mozgu, te PMCA3 i 4 u hipokampusu miševa St8sia1 null ukazujući na različitu staničnu potrebu za pojedinim izoformama različitih kinetičkih svojstava. Analizom submembranske lokalizacije navedenih proteina utvrđen je proces njihove redistribucije u analiziranim regijama mozga miševa St8sia1 null. Analizom enzimskih aktivnosti NKA i PMCA utvrđeno je kako dolazi do pada aktivnosti u moždanoj kori i malome mozgu miševa St8sia1 null uslijed ukupnih biokemijskih promjena uzrokovanim promijenjenim gangliozidnim sastavom membrane. Dodavanjem egzogenih gangliozida b- serije uspostavljen je porast enzimske aktivnosti NKA i PMCA, dajući ovom istraživanju translacijski potencijal. Rezultati istraživanja nedvojbeno pokazuju da promijenjen sastav gangliozida ima dalekosežne posljedice po funkcioniranje ubikvitarnih staničnih membranskih prijenosnika iona.Mice models with altered biosynthesis of glycosphingolipids gangliosides have altered membrane lipid environment necessary for the proper function of membrane proteins. The aim of this thesis was to systematically determine the effect of altered ganglioside composition on gene and protein expression, submembrane localization of specific isoforms and subunits of Na+, K+-ATPase (NKA), plasma membrane Ca2+-ATPase (PMCA) and neuroplastin (Np), and enzyme activity of NKA and PMCA in different brain regions of St8sia1 null mice. Gene expression analysis revealed changes in expression profiles of different PMCA isoforms and NKA subunits in null mice compared to their controls, indicating the different cellular need for specific isoforms. Neuroplastin gene expression was higher in all analysed regions. Higher protein content of catalytic NKA subunits and PMCA2 isoforms in the cortex, PMCA4 in the cerebellum, and of PMCA3 and PMCA4 isoforms in the hippocampus was determined in null mice illustrating the cellular needs for specific subunits with differing kinetic parameters. Altered submembrane localization of investigated proteins shows their redistribution between different membrane subdomains. Described biochemical changes stemming from altered ganglioside composition, cause lower enzyme activities of NKA and PMCA determined in cortices and cerebella of null mice. We were able to rescue NKA and PMCA activity by administration of exogenous b- series gangliosides, giving this research translational potential. The results of this thesis unequivocally show that changes in ganglioside microenvironment have considerable consequences on the function of membrane ion transporters

Motorički učinci klostridijskih neurotoksina u središnjem živčanom sustavu (MEFCLO) - plan upravljanja istraživačkim podacima

Motorički učinci klostridijskih neurotoksina u središnjem živčanom sustavu (MEFCLO) - plan upravljanja istraživačkim podacim

Interactions of B-lymphocytes and bone cells in health and disease

Bone remodeling occurs through the interactions of three major cell lineages, osteoblasts, which mediate bone formation, osteocytes, which derive from osteoblasts, sense mechanical force and direct bone turnover, and osteoclasts, which mediate bone resorption. However, multiple additional cell types within the bone marrow, including macrophages, T lymphocytes and B lymphocytes influence the process. The bone marrow microenvironment, which is supported, in part, by bone cells, forms a nurturing network for B lymphopoiesis. In turn, developing B lymphocytes influence bone cells. Bone health during homeostasis depends on the normal interactions of bone cells with other lineages in the bone marrow. In disease state these interactions become pathologic and can cause abnormal function of bone cells and inadequate repair of bone after a fracture. This review summarizes what is known about the development of B lymphocytes and the interactions of B lymphocytes with bone cells in both health and disease

Istraživanje stavova i prakse objavljivanja radova u otvorenom pristupu među hrvatskim znanstvenicima - anketni upitnik

Anketni upitnik izrađen za potrebe istraživanja stavova i prakse objavljivanja radova u otvorenom pristupu među hrvatskim znanstvenicima. Anketa je provedena od u on-line obliku, od 23. veljače do 21. ožujka 2023.g

Cell Free DNA Methylation of RASSF1A and PRSS21 Genes in Blood and Semen of Patients with Nonseminomatous Testicular Germ Cell Tumors

Tumori zametnih stanica testisa (TZST) su najčešća neoplazija koja pogađa mlađu mušku populaciju. Dijele se na seminome i neseminome (NSE). Potvrda dijagnoze TZST neizostavno uključuje radikalnu orhidektomiju te je pouzdana neinvazivna dijagnostička metoda potrebna za raniju dijagnostiku. Analiza slobodnocirkulirajuće nestanične DNA (cfDNA) iz tjelesnih tekućina je perspektivan neinvazivan postupak za dijagnozu onkoloških pacijenata. Metilacija genomske DNA (gDNA) gena RASSF1A i PRSS21 iz tkiva TZST-a se pokazala perspektivnim biomarkerom. Cilj rada je utvrditi potencijal metilacije cfDNA gena RASSF1A i PRSS21 iz krvi i ejakulata kao biomarkera za identifikaciju pacijenata s NSE. Pirosekvenciranjem je istražena stopa metilacije cfDNA promotorske regije gena RASSF1A i PRSS21 iz krvi i ejakulata pacijenata s potvrđenom dijagnozom NSE i zdravih dobrovoljaca bez prijašnje dijagnoze TZST-a te gDNA iz tumorskog tkiva i okolnog zdravog tkiva pacijenata s NSE. Hipermetilirana gDNA RASSF1A bila je detektirana u tkivu NSE naspram okolnog zdravog tkiva. U gena PRSS21 nije detektirana razlika u stupnju metilacije gDNA. Kod pacijenata s NSE detektirana je hipermetilacija cfDNA gena RASSF1A u krvi, dok je u ejakulatu detektirana hipermetilacija cfDNA gena PRSS21. Metilacija cfDNA gena RASSF1A i PRSS21 je pokazala višu osjetljivost i specifičnost od biomarkera koji su trenutno u kliničkoj upotrebi. Ovim istraživanjem je potvrđen potencijal metilacije cfDNA gena RASSF1A u krvi te je otkriven potencijal metilacije cfDNA gena PRSS21 u ejakulatu kao dijagnostičkih biomarkera pacijenata s NSE.Testicular germ cell tumors (TGCT) are the most common malignancy among young males. TGCT are subdivided into seminomas and nonseminomas (NSE). Confirmation of a TGCT diagnosis always includes radical orchidectomy, making a reliable noninvasive diagnostic method required for earlier diagnosis. Analysis of circulating cell-free DNA (cfDNA) from body liquids is a perspective noninvasive procedure for diagnosis of oncological patients. Genomic DNA methylation (gDNA) of RASSF1A and PRSS21 genes in the tissue of TGCT has been shown as a potential biomarker. The aim of this study was to assess the potential of cfDNA methylation of genes RASSF1A and PRSS21 in the blood and ejaculate as biomarkers for patients with NSE. Pyrosequencing was used to analyze cfDNA methylation of genes RASSF1A and PRSS21 in blood and ejaculate of patients with a confirmed diagnosis of NSE and healthy donors with no prior diagnosis of TGCT as well as in gDNA from the tumor tissue and the surrounding healthy tissue of patients with NSE. RASSF1A was hypermethylated in gDNA of tumor tissue. No difference in gDNA methylation levels was found in PRSS21. In NSE patients hypermethylated RASSF1A was detected in cfDNA isolated from the blood, while hypermethylated PRSS21 was detected in cfDNA isolated from the ejaculate. Methylation of RASSF1A and PRSS21 cfDNA shows higher sensitivity and specificity than the currently used clinical biomarkers. This study confirms the potential of methylation of RASSF1A in cfDNA from blood and discovers the methylation of PRSS21 in cfDNA from the ejaculate as diagnostic biomarkers of patients with NSE

Successful emergency Lichtenberger lateralisation for immediate bilateral laryngeal immobility after total thyroidectomy: a CARE case report

Objective: This case report discusses a successful emergency Lichtenberger lateralisation procedure after immediate bilateral laryngeal immobility, occurring after total thyroidectomy. Methods: A 63-year-old female with right-sided vocal fold paralysis due to compression by a multinodular thyroid goitre underwent total thyroidectomy, which resulted in immediate post-operative bilateral vocal fold immobility. The patient had acute-onset post-operative dyspnoea, was promptly re-intubated, and an emergency lateralisation Lichtenberger suture was placed over the right vocal fold and fixated on the outer surface of the neck. Results: After two weeks, her right vocal fold recovered first, with the suture still in place. At four weeks, both vocal folds regained function and the suture was extracted. Conclusion: The take-away message is that an emergency lateralisation suture may be a viable option in maintaining airway patency, while allowing for normal deglutition, in patients who would otherwise be candidates for prolonged intubation, posterior cordotomy, medial arytenoidectomy or tracheostomy

Bearing variant alleles at uridine glucuronosyltransferase polymorphisms UGT2B7 -161C > T (rs7668258) or UGT1A4*3 c.142 T > G (rs2011425) has no relevant consequences for lamotrigine troughs in adults with epilepsy

Purpose: To estimate whether epilepsy patients with variant UGT2B7 -161C > T (rs7668258) or UGT1A4*3 c.142 T > G (rs2011425) alleles differ from their wild-type (wt) peers in exposure to lamotrigine. Methods: Consecutive adults on lamotrigine monotherapy or lamotrigine + valproate co-treatment undergoing routine therapeutic drug monitoring, otherwise generally healthy and free of interacting drugs, were genotyped for UGT2B7 -161C > T and UGT1A4*3 c.142 T > G. Heterozygous, variant homozygous, or combined heterozygous/variant homozygous subjects were compared to their wt controls for dose-adjusted lamotrigine troughs with adjustment for age, sex, body weight, rs7668258/rs2011425, polymorphisms of efflux transporter proteins ABCG2 c.421C > A (rs2231142) and ABCB1 1236C > T (rs1128503), and level of exposure to valproate using covariate entropy balancing. Results: Of the 471 included patients, 328 (69.6%) were on monotherapy and 143 were co-treated with valproate. Dose-adjusted lamotrigine troughs in UGT2B7 -161C > T heterozygous (CT, n = 237) or variant homozygous (TT, n = 115) subjects were closely similar to those in their wt controls (CC, n = 119): geometric means ratios (GMRs) (frequentist and Bayes) 1.00 (95%CI 0.86-1.16) and 1.00 (95%CrI 0.83-1.22) for CT vs. CC; and 0.97 (0.81-1.17) and 0.97 (0.80-1.20) for TT vs. CC subjects. Lamotrigine troughs were also closely similar in UGT1A4*3 c.142 T > G variant carriers (n = 106: 102 TG + 4 GG subjects) and wt controls (TT, n = 365): GMR = 0.95 (0.81-1.12) frequentist, 0.96 (0.80-1.16) Bayes. GMRs for variant carriers vs. wt controls were around unity also at different levels of exposure to valproate. Conclusion: Dose-adjusted lamotrigine troughs in epilepsy patients with variant UGT2B7 -161C > T or UGT1A4*3 c.142 T > G alleles are equivalent to those in their respective wt peers