Brain-derived neurotrophic factor (BDNF) in psychiatric patients with schizophrenia and major depressive disorder

Moždani neurotrofni čimbenik (BDNF) jest čimbenik rasta koji ima veliku ulogu u preživljavanju, rastu i diferencijaciji živčanih stanica u središnjem i perifernom živčanom sustavu. Potiče neurogenezu i plastičnost neurona te ostale procese koji doprinose poboljšanoj funkciji hipokampusa, što ima veliki utjecaj na memoriju i učenje. Osim toga, ima značajan učinak na morfologiju dendrita i razvoj aksona. U zadnja tri desetljeća sve je veći broj dokaza o njegovoj uključenosti u patofiziologiju mnogih psihijatrijskih bolesti i poremećaja, pa tako i shizofrenije i velikog depresivnog poremećaja. Snižene razine BDNF-a pronađene su u krvi pacijenata oboljelih od navedenih bolesti. Psihički poremećaji rezultat su genetskog nasljeđa i utjecaja okoline, te zbog svoje kompleksnosti predstavljaju veliki problem u društvu. Cilj ovog rada je izmjeriti i usporediti koncentracije BDNF-a u serumu psihijatrijskih bolesnika oboljelih od shizofrenije i velikog depresivnog poremećaja, s nastojanjem da se pronađe objektivna molekula koja bi poslužila kao biomarker, te kako bi se istražio mogući doprinos BDNF-a u diferencijalnoj dijagnostici tih dvaju poremećaja. U istraživanje je bilo uključeno 69 pacijenata Klinike za psihijatriju KBC-a Sestre milosrdnice, od kojih 31 boluje od velikog depresivnog poremećaja, a 38 od shizofrenije. Ispitanici su različite životne dobi, a pripadnost po spolu je neujednačena (veći broj ženskih ispitanica). Koncentracija BDNF-a u serumu određena je ELISA (engl. Enzyme-Linked Immunosorbent Assay) metodom pomoću gotovog reagens kita, čija se reakcija temelji na nekompetitivnom sendvič principu. Statističkim računalnim programom (MedCalc Software, Mariakerke, Belgija) vršila se statistička obrada dobivenih podataka. Normalna distribucija varijabli ispitivana je D'Agostino-Pearsonovim testom, na temelju kojeg smo se opredijelili za parametrijske testove za uspoređivanje skupova podataka. Rezultati su pokazali da nema značajne razlike u koncentraciji BDNF-a u serumu ove dvije skupine pacijenata, što bi značilo da u ovom pogledu određivanje BDNF-a nema diferencijalno dijagnostičku vrijednost. Osim toga, uspoređivane su i vrijednosti između muških i ženskih ispitanika, bolesnika koji su na terapiji (Farm bolesnici), bolesnika s određenim polimorfizmom SERT-a, te se ispitivala povezanost razine BNDF-a i dobi ispitanika. Ni jedno od ovih ispitivanja nije dalo statistički značajan rezultat. Unatoč tome, preporuka je ponoviti slično istraživanje na većem broju ispitanika i u bolje kontroliranim uvjetima.Brain-derived neurotrophic factor (BDNF) is a growth factor, which has a major role in survival, growth and differentiation of neurons in central and peripheral nervous systems. Its positive influence on neurogenesis and neuronal plasticity has a big effect on learning and memory. Furthermore, BDNF was also recognised as a significant factor in the growth of axons and dendrite formation. Increasing evidence over the last three decades has indicated that the pathophysiology of many psychiatric diseases and disorders, including schizophrenia and major depressive disorder, involve brain-derived neurotrophic factor. Reduced BDNF levels have been observed in the blood of patients suffering from these diseases. Psychological disorders are a result of genetic and environmental influences, and due to their complexity they represent a big problem in society. The aim of this study is to measure and compare BDNF concentrations in serum of psychiatric patients suffering from schizophrenia and major depressive disorder, with the intention of finding an objective molecule that would serve as a biomarker, and to investigate the possible BDNF contribution to differential diagnosis of these two disorders. This study included 69 patients, of which 31 are suffering from major depressive disorder and 38 from schizophrenia, and which are treated at the Psychiatric Clinic of University Hospital Centre „Sestre milosrdnice“. Examinees differ by age and sex, but there are many more female participants. Serum BDNF concentration is determined by ELISA (Enzyme-Linked Immunosorbent Assay) method using the ready-made reagent kit, in which the reaction is based on noncompetitive sandwich principle. A computer statistical program (MedCalc Software, Mariakerke, Belgium) was used for the statistical analysis. Normal distribution of variables was tested using D'Agostino-Pearson test, that lead us to using parametric testing for data comparison. The results have shown that there is no significant difference in the serum BDNF concentration in these two groups of patients, meaning that from this point of view, measuring BDNF levels has no differential diagnostic value. Beside that, the comparisons of values between male and female examinees, patients that are on therapy (Pharm patients), patients with determined SERT polymorphism have been done, and the correlation of BDNF levels and age has also been tested. Neither one of these investigations has given us a statistically significant result. Nevertheless, it would be of interest to further explore this issue on a larger sample size and in more controlled environmental conditions