A. Suszka-Świtek

Escitalopram affects spexin expression in the rat hypothalamus, hippocampus and striatum

BACKGROUND Spexin (SPX) is a recently discovered neuropeptide that exhibits a large spectrum of central and peripheral regulatory activity, especially when considered as a potent anorexigenic factor. It has already been proven that antidepressants, including selective serotonin reuptake inhibitors (SSRI), can modulate peptidergic signaling in various brain structures. Despite these findings, there is so far no information regarding the influence of treatment with the SSRI antidepressant escitalopram on brain SPX expression. METHODS In this current study we measured SPX mRNA and protein expression in the selected brain structures (hypothalamus, hippocampus and striatum) of rats chronically treated with a 10mg/kg dose of escitalopram using quantitative Real-Time PCR and immunohistochemistry. RESULTS Strikingly, long-term (4 week) drug treatment led to the downregulation of SPX expression in the rat hypothalamus. This supports the hypothesis that SPX may be involved in the hypothalamic serotonin-dependent actions of SSRI antidepressants and possibly also in the central mechanism of body mass increase. Conversely, SPX expression increased in the hippocampus and striatum. CONCLUSIONS This is the first report of the effects of a neuropsychiatric medication on SPX expression in animal brain. Our findings shed a new light on the pharmacology of antidepressants and may contribute to a better understanding of the alternative mechanisms responsible for antidepressant action.

Morphological and enzymatic changes caused by a long-term treatment of female rats with a low dose of gonadoliberin agonist and antagonist

Summary Background Long-term treatment with gonadoliberin analogs is used to block the hypothalamic-pituitary-gonadal axis. The use of these agents is generally considered to be safe; however, some observations suggest the possibility of adverse effects. Material/Methods We investigated whether a 3-months administration of a low dose (6 μg/kg b.w.) of dalarelin – a new agonist, and cetrorelix – a known antagonist of GnRH to female rats causes morphological changes in pituitary gland, ovaries, uterus and liver (HE and VG staining); effects on pituitary, hepatic and blood enzyme activities (histochemical and kinetic methods, respectively), and on the blood lipid profile (colorimetric methods); and to what extent these changes are reversible. Results Applying analogs effectively inhibited ovulation, affected the uterine endometrium and changed histological appearance of the liver (e.g., steatosis). They altered activities of marker enzymes of cellular respiration, gluconeogenesis and intracellular digestion in the liver and, partially in the pituitary gland, caused undesirable changes in the activities of aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and creatine kinase, and a concentration of cholesterol HDL fraction and triglycerides in the blood. Both morphological and enzymatic effects were more evident after antagonist administration; changes in the blood lipid profile were more evident after agonist administration. In both analogs histological and enzymatic changes persisted a relatively long time after the discontinuation of the treatment. Conclusions The low dose of dalarelin and cetrorelix is sufficient to cause limited damage of hepatic cells and may modify the function of pituitary, ovaries, uterus and liver as well as other organs, even after discontinuation of the treatment.

Evaluation of Apoptosis in the Liver Preserved by Simple Hypothermia Using Histidine-Tryptophan-Ketoglutarate and Prolactin-Modified Histidine-Tryptophan-Ketoglutarate Solution

INTRODUCTION Organ ischemia is accompanied by cell death due to apoptosis. It occurs together with necrosis, which has more unfavorable consequences due to the release of cytokines that activate the inflammatory response cascade. The aim of this study was to assess the degree of apoptosis in porcine livers preserved by simple hypothermia for 12 hours using standard solutions (University of Wisconsin [UW] and histidine-tryptophan-glutarate [HTK]), and to evaluate the effect of prolactin (PRL) addition to the HTK solution. MATERIALS AND METHODS The study was performed on the livers of Great White breed pigs, after inducing 30 minutes of warm ischemia (WIT30), followed by 30 minutes of perfusion-cooling to 4°C, and 12 hours of preservation. Livers were evaluated after preservation in Ringers solution (control); UW (control reference fluid); HTK and HTK modified by the addition of prolactin (20 UI/L. Apoptosis was assessed in liver sections by the TdT-mediated dUTP nick-end labeling method after 12-hour preservation. We adopted a prevalence scale ranging from 0 to 3+, depending on the number of observed nuclei and apoptotic bodies (AB). RESULTS Preservation in Ringers solution yielded AB distribution at the 1+ level, with a lack of characteristic localization resulting from necrotic lesions. Analysis of the livers preserved in the UW solution showed high, 3+ level of AB presence. For the tested HTK solution, the observed ABs localization value was 3+, whereas in the PRL-modified group it was also 3+, but with a tendency to move from zone II to cluster III, which is important for liver metabolic functions. CONCLUSIONS PRL improved the preservation properties of HTK for porcine livers by maintaining a high apoptosis level. It may stabilize cell membranes thus reducing the oncotic necrosis, promoting increased apoptosis during simple hypothermia.

Evaluation of Cysteine Effect on Redox Potential of Porcine Liver Preserved by Simple Hypothermia

INTRODUCTION Cysteine (cys), a thiol amino-acid, is involved in de novo glutathione (GSH) synthesis in the extra- and intracellular space. It is also probably involved in the anaerobic glycolysis process. Both these facts may affect the metabolic condition of the liver preserved by simple hypothermia for transplantation. The aim of the study was to verify whether cysteine addition to histidine-tryptophan-ketoglutarate (HTK) organ preservation solution showed a positive effect on liver redox potential after 12-hour preservation in simple hypothermia. MATERIALS AND METHODS After collecting livers of Great White breed pigs that underwent 30 min of warm ischemia, before 30-min perfusion and cooling to 4°C with modified HTK solution containing cysteine prior to 12 h of preservation. Activity of glutathione reductase (GR), glutathione peroxidase (GPx), and superoxide dismutase (SOD) was determined in liver homogenates after perfusion and after the preservation period. The results were compared with pure HTK, Ringers and reference University of Wisconsin (UW) solutions. RESULTS 30 min of perfusion and 12 h of cold preservation (CIT) in the Ringers solution markedly increased GPx, SOD, and GR activities in liver homogenates compared with the activity using other fluids. After 12-h CIT the activities of GR, GPx and SOD were significantly higher in cys-modified HTK solution than the control HTK solution. They were comparable to the values recorded for the UW group. CONCLUSIONS Addition of cys to the HTK solution positively influenced the total pool of free radical scavengers in a liver undergoing 12-hour ischemia in the simple hypothermia, which was reflected in the elevated redox enzyme activity possibly due to cys participation in GSH synthesis.

Interleukin-6 Concentration in the Transgenic Pig's Liver Preserved for 24 Hours in Biolasol Solution

INTRODUCTION Increasing the human lifespan contributes to a higher number of patients with end-stage organ failure, which in turn stimulates the search for alternative sources. Xenotransplantation seems to be a promising approach in this respect. OBJECTIVE Analysis of changes in interleukin (IL)-6 concentration during 24-hour preservation of transgenic swine livers, depending on the kind of transgenesis and preservation solution used. MATERIALS AND METHODS The experiment was carried out in swine livers with transferred human genes that were divided into 5 groups. The following human genes were transferred: α1,2-fucosyltransferase (group I and II), α-galactosidase (III), combined α1,2-fucosyltransferase/α-galactosidase transgene (IV), and livers without modification (V). The livers were perfused and subsequently stored for 24 hours in Ringers (group I) or Biolasol solutions (II-V). Reflush was then performed. IL-6 concentration was analyzed in the solution samples collected at the beginning and end of perfusion, and after 24 hours of preservation. ELISA was used to evaluate IL-6 concentration. RESULTS In liver homogenates from group I, IL-6 concentration after 24 hours of preservation increased by 8.24% compared to the levels observed after perfusion, whereas in the other groups IL-6 concentration decreased. The most significant decrease, 49.51%, was observed in group II; the least significant in group IV, 10.72%. In case of supernatants, a statistically significant increase of AUC0-30min level in relation to perfusion was observed in every group after 24-hour preservation and reperfusion. The highest values of AUC0-30min were observed in group I (α1,2-fucosyltransferase, Ringers solution). CONCLUSION The study indicates the hepatoprotective action of Biolasol solution.

Neuroleptics Affect Kisspeptin mRNA Expression in the Male Rat Hypothalamus and Hippocampus

Introduction: Kisspeptin has a multidirectional neuroendocrinal activity. It is especially considered to be a central regulator of reproductive function. Numerous data proved that neuroleptic administration may affect the peptidergic signaling in the various brain structures. However, there is no information concerning the relationship between treatment with neuroleptics and brain kisspeptin mRNA expression. Methods: We assessed the kisspeptin mRNA level in the hypothalamus and hippocampus of rats shortly and chronically (28 days) treated with haloperidol, chlorpromazine, and olanzapine using a quantitative Real-Time PCR method. Results: We have shown that all studied neuroleptics injected chronically have the ability to downregulate the kisspeptin mRNA expression in the hypothalamus, which may suggest the presence of an alternative mechanism for their orexigenic side effects. Long-term treatment with chlorpromazine increased the level of kisspeptin mRNA expression in the hippocampus. Discussion: Our results shed a new light on the pharmacology of antipsychotics and may contribute to a better understanding of alternative mechanisms responsible for their action. The study also highlights a complex nature of potential connections between dopamine transmission and brain kisspeptin pathways.

Expression of cytochrome P450 2C and 3A in female rat liver after long-term administration of gonadoliberin analogs.

OBJECTIVES Gonadoliberin (GnRH) analogs may be expected to indirectly modify growth hormone (GH) total concentration and its 24-h secretion profile. As a consequence, changes in the levels of GH may modify the mechanism of sex-dependent cytochromes P450 (CYP450) synthesis, including the expression of transcriptional factors. The aim of the study has been to evaluate the effect of long-term administration of a low dose of GnRH analogs on hepatic expression of CYP2C and CYP3A isoforms, and the transcription factors: pregnane X receptor (PXR), hepatocyte nuclear factor 4α (HNF4α), HNF6 and signal transducers and activators of transcription 5b (STAT5b). MATERIAL AND METHODS The study was carried out on adult female Sprague-Dawley rats during a 3-month treatment with dalarelin (GnRH agonist) and cetrorelix (GnRH antagonist), at a daily intraperitoneal injection (i.p.) dose of 6 μg/kg body weight/day, and 1, 2, and 4 weeks after treatment discontinuation. The concentrations of ovarian hormones and GH in the blood serum were determined by radioimmunoassay and enzyme-linked immunosorbent assay (ELISA) method, respectively. Then, the expression of hepatic CYP450s (reverse transcription polymerase chain reaction - RT-PCR, Western blot and immunohistochemistry) and transcription factors (RT-PCR) was evaluated. RESULTS We have found that cetrorelix induces changes in the circadian pattern of GH secretion and enhances GH blood concentrations. These changes may cause increased expression of both, female-specific CYP450s (especially CYP3A9), and HNF4α/HNF6 transcription factors. Decrease in GH blood concentrations, resulting from the effect of dalarelin, may promote inhibition of female-specific CYP2C12 and CYP3A9 isoforms as well as STAT5b transcription factor. Slight changes in sex-independent CYP3A1 protein expression caused by GnRH analogs were also observed. CONCLUSIONS In adult female rats, HNF4α/HNF6 and STAT5b seem to be crucial for the regulation of GnRH antagonist/GH- and GnRH agonist/GH-dependent pattern of CYP450 expression, respectively.

Comparison of Endothelial Nitric Oxide Synthase and Endothelin-1 Levels in Kidneys Removed From Living Pigs After Cardiac Arrest and Brain Death

OBJECTIVES The aim of this paper was to describe differences between levels of endothelial nitric oxide synthase (NOS-3) and endothelin-1 (ET-1) in swine kidneys removed from living donors (group I) and after inducing brain death by brain herniation (group II) and cardiac arrest (group III). METHODS Each group consisted of 3 animals who underwent dual renal removal procedure; kidneys were further rinsed according to standardized procedure with Biolasol perfusion liquid, stored for 24 hours (4°C), and rinsed again. Renal specimens of 4 g mass, including renal cortex and medulla, were collected before and after perfusion (times 0 and 1), after 12 hours (time 2), and after reperfusion (time 3). Enzyme-linked immunosorbent assay was used to describe levels of NOS-3 and ET-1 in collected tissues homogenates. Mann-Whitney U test was used to compare results in groups in relation to total protein content (ng/mg), and the correlation between the 2 substances was measured with the use of Spearman rho. RESULTS Group I presented low and stable levels of NOS-3 in all time intervals (averages, 0.73, 0.99, 0.52, and 0.89, respectively). Level sof ET-1 were similar (0.87, 0.63, 0.69, and 0.86, respectively), and significant correlation between levels of the 2 substances was observed. Increased levels of NOS-3 (1.89 and 1.86) and ET-1 (1.38 and 1.49) were observed directly after removal in groups II and III and further maintained during organ storage. No correlation in group I was observed, and after perfusion significantly lower level of NOS-3 was observed in kidneys removed after brain death in relation to group III (1.77 vs 2.60). CONCLUSIONS The lowest and stable levels of NOS-3 and ET1 during storage were observed in kidneys removed from living donors. Levels of analyzed substances in this group showed correlation in subsequent time intervals.

Endothelial Nitric Oxide Synthase and Endothelin-1 Expression in the Early Post–Porcine Kidney Autotransplantation Period

BACKGROUND The aim of this study was the assessment of endothelial nitric oxide synthase (eNOS) and endothelin-1 (EDN-1) expression in porcine kidneys on the 14th and 30th days after the autotransplantation procedure. METHODS The research was conducted on 12 animals that underwent a left renal transplantation procedure with further standardized rinsing and 24-hour storage in 4°C; subsequently, the kidneys were implanted in the right retroperitoneal space after right-sided nephrectomy. Removed kidneys were examined (group 0). Six randomly chosen animals (group 1) were under observation for 14 days and 6 others (group 2) for 30 days. RESULTS After these observation periods, euthanasia was performed on the animals and 4-g samples were collected from the renal cortex and medulla. The Western blot technique was used to detect the eNOS and EDN-1 expression at the protein level. The obtained results are presented as absolute values of integrated optical density. Stable graft function was observed in all animals from the 2nd day after the procedure. eNOS in group 1 reached the mean value of 1.064 and was statistically significantly lower than in group 2 (2.085) or in the control group 0 (3.318). In the case of EDN-1 expression on 14th day after transplantation, the medium level was reported (0.248), which was similar to group 0 (0.216), whereas group 2 presented values 2 times higher (0.743). CONCLUSIONS A lowered eNOS level in the organ was observed on the 14th day after autotransplantation of a pig kidney; further enzyme normalization is associated with increased EDN-1 expression.

Cytochrome P450 3 A Expression in Pigs Livers After 24-Hour Preservation in Biolasol Solution Depending on the Type of Transgenesis

BACKGROUND An insufficient number of organs for transplantation shows the need for the development of new technologies. Xenotransplantation might be the answer. OBJECTIVE To determine if the type of transgenesis influences the level of CYP3A4, which takes an active part in xenobiotics metabolism in livers after 24-hour storage, depending on the kind of solution used for preservation. MATERIALS AND METHODS The experiment was carried out on 30 livers of Polish White Landrace divided into 5 groups depending on transgene type. The following human genes were transferred: α1,2-fucosyltransferase (groups I and II), α-galactosidase (III), combined α1,2-fucosyltransferase/α-galactosidase transgene (IV), and livers without modification (V). The livers were perfused and subsequently stored for 24 hours in Ringers solution (group I) or Biolasol solution (II-V). Reperfusion/reflush was performed. CYP3A29 isomer concentration was analyzed in liver specimens collected twice: 30 minutes after perfusion and 30 minutes after reperfusion/reflush. Expression of mRNA CYP3A29 was marked using RT-PCR analysis and of protein CYP3A29 using Western blotting technique. RESULTS The most significant decrease in protein CYP3A29 expression after 24-hour preservation was observed in group I (55.88% decrease), while the least significant was observed in group IV (10.44% decrease). mRNA expression evaluation was similar: the most significant decrease was observed in group I (87.8% decrease) and the least significant in group III (4.6% decrease). CONCLUSION α1,2-Fcosyltransferase transgene seems to influence mRNA and protein CYP3A expression in case of liver grafting and preservation for transplantation. CYP3A expression was also influenced by the kind of preservation solution used.