Donatas Stakišaitis

Influence of Sodium Valproate on Sodium and Chloride Urinary Excretion in Rats, Gender Differences

Evidence exists indicating that sodium valproate (VPA) increases diuresis in rats. The chloriuretic and natriuretic effect of VPA has not previously been investigated, so the aim of the present study was to define the peculiarities of 24-hour urinary sodium (Na) and chloride (Cl) excretion in young adult Wistar rats of both genders, and to evaluate the effects of VPA. 24-Hour urinary Na, Cl, creatinine and pH levels were measured in 28 control intact Wistar rats and 26 Wistar rats after a single intragastric administration of 300 mg/kg VPA. After VPA administration, 24-hour diuresis and 24-hour diuresis per 100 g of body weight were significantly higher in VPA rats of both genders. 24-Hour urine Na and Cl excretion were significantly higher in VPA male and VPA female rats than in gender-matched controls. The 24-hour urinary Cl excretion was found to be significantly higher in VPA male than in VPA female rats. The study data show that VPA, alongside the diuretic effect, enhances Na and Cl excretion with urine. The 24-hour chloriuretic response to VPA in male rats was significantly higher than in female rats. The mechanism of such a gender-related effect is not yet clear.

Sodium valproate stimulates potassium and chloride urinary excretion in rats: gender differences

BackgroundThe diuretic effect of valproates and its relation to urinary potassium (K+) and chloride (Cl-) excretion have not yet been investigated, so the aim of this study was to evaluate the influence of a single dose of sodium valproate (NaVPA) on 24-h urinary K+ and Cl- excretion in young adult Wistar rats of both genders. For measurement of K+ in urine, the same animals and samples as in our earlier publication were used (Pharmacology 2005 Nov, 75:111–115). The authors propose a new approach to the pathophysiological mechanisms of NaVPA effect on K+ and Cl- metabolism.Twenty six Wistar rats were examined after a single intragastric administration of 300 mg/kg NaVPA (13 NaVPA-male and 13 NaVPA-female), 28 control intact Wistar rats (14 males and 14 females) were studied as a control group. The 24-h urinary K+, Cl-, creatinine and pH levels were measured.ResultsTotal 24-h diuresis and 24-h diuresis per 100 g of body weight were found to be significantly higher in NaVPA-rats of both genders than in rats of the control group (p < 0.05). The data showed NaVPA to enhance 24-h K+ excretion in NaVPA-males and NaVPA-females with significant gender-related differences: 24-h K+ excretion in NaVPA-male rats was significantly higher than in control males (p = 0.003) and NaVPA-female rats (p < 0.001). Regarding the 24-h K+ excretion, NaVPA-female rats did not show a statistically significant difference versus females of the control group (p > 0.05). 24-h urinary K+ excretion per 100 g of body weight in NaVPA-male rats was significantly higher than in control males (p = 0.025). NaVPA enhanced Cl- urinary excretion: 24-h Cl- urinary excretion, 24-h urinary Cl- excretion per 100 g of body weight and the Cl-/creatinine ratio were significantly higher in NaVPA-male and NaVPA-female rats than in gender-matched controls (p < 0.05). 24-h chloriduretic response to NaVPA in male rats was significantly higher than in female rats (p < 0.05).ConclusionNaVPA causes kaliuretic and chloriduretic effects with gender-related differences in rats. Further investigations are necessary to elucidate the mechanism of such pharmacological effects of NaVPA.

Sodium valproate effect on the structure of rat glandule thymus: Gender-related differences

Sodium valproate (VPA) was shown to inhibit cell growth mechanisms such as cell cycle arrest, proliferation suppression, increase of apoptosis. Many aspects of the contribution of the VPA pharmacological mechanisms and their significance in gender-related processes have not been investigated. In our study, we have tested hypothesis that the influence of VPA on thymus weight and structure might be gender-related. The thymus of Wistar rats of both genders aged 8 weeks was investigated in the following groups (n = 6 each): controls, treated with VPA, castrated male and female treated with VPA, and the castrated control of both genders. The thymus weight, structural changes and area of cortical and medullar parts of the gland in slides stained with hematoxylin and eosin and immunohistochemically were assessed. A comparison of thymus weight of castrated male and of castrated VPA-treated male rats showed a significant thymus weight loss after VPA treatment (0.66 ± 0.04 g vs. 0.43 ± 0.03 g, p < 0.05). The treatment with VPA caused an about 6-fold (0.39 ± 0.12 vs. 0.07 ± 0.03) increase of Hassalls corpuscles (HCs) numbers per 1mm(2) in male and more than 4-fold increase (0.46 ± 0.07 vs. 0.10 ± 0.04) in female rats. In castrated males and females, the HCs number was also increased, but this increase was statistically significant only in male animals vs. controls (0.46 ± 0.10 vs. 0.07 ± 0.03, p < 0.001 in males; 0.29 ± 0.13 vs. 0.10 ± 0.04, p > 0.05 in females). When castrated male and female rats were treated with VPA, further increase of HC numbers was found. In our study, VPA has inhibited the proliferative capacity of thymocytes by diminishing the thymus weight and inducing a differentiation of thymic medullar epithelial cells into HCs. The diminishing of the gl. thymus weight under the influence of VPA was significant in castrated male rats. The number of HCs increased in animals of both genders under the influence of VPA. Gender differences in HCs development were noted in castrated animals.

Sodium valproate enhances urethane tumorigenicity in lungs of male but not female mice

In the study, the possible effect of sodium valproate (NaVP) on urethane-induced lung tumors in mice has been evaluated. BALB/c mice (n = 120; 4–6 weeks old, both sexes) were used in the following groups: 1) urethane-treated, 2) urethane–NaVP-treated, 3) only NaVP-treated, 4) control. In the same groups, castrated male mice (n = 48) were investigated. Urethane was given by intraperitoneal injections 10 mg/mouse, twice a week, the total dose 50 mg/mouse. In NaVP-treated mice, the 0.4 % NaVP aqueous solution was offered to mice ad libitum. The duration of the experiment was 6 months. The number of tumors per mouse in urethane–NaVP-treated males was significantly higher than in those treated with urethane only (13.82 ± 1.12 vs 6.77 ± 0.43, p < 0.0001). No significant difference in the number of tumors per mouse was revealed while comparing the female urethane- and urethane–NaVP-treated groups (6.50 ± 0.79 vs 8.15 ± 0.55, p = 0.105). No difference in the number of tumors per mouse was found in urethane–NaVP-treated castrated males as compared with urethane-treated castrated males. However, in the urethane–NaVP-treated castrated males the number of tumors per mouse was significantly lower than in analogous non-castrated males (7.8 ± 1.67 vs 13.82 ± 1.12, p < 0.01). NaVP combined with urethane potentiates urethane tumorigenicity in BALB/c non-castrated but not in female and castrated male mice. These data indicate an important role of testosterone in the urethane-NaVP induced lung tumorigenesis.

Sex-related differences of urethane and sodium valproate effects on Ki-67 expression in urethane-induced lung tumors of mice

The aim of the present study was to evaluate sex differences in tumorigenesis by assessing the number of Ki-67-positive cells [Ki-67(+)] in urethane-induced mice lung tumors and the effect of sodium valproate (NaVP) in BALB/c mice. Gonad-intact and gonadectomized female and male mice were divided into the following groups: i) Treated with urethane, ii) treated with urethane and NaVP and iii) gonad-intact or gonadectomized control. Urethane (total 50 mg/mouse) was injected intraperitoneally. The NaVP 0.4% solution was administered orally for 6 months. Histologically, lung tumors were divided into adenomas and adenocarcinomas and assessed immunohistochemically using antibodies against Ki-67. The Ki-67(+) was calculated per one mm2 of a tumor. In adenomas, Ki-67(+) in the urethane-treated gonad-intact males was significantly higher than in females (P=0.001) and in castrated males (P<0.01); Ki-67(+) in adenomas of the urethane-treated gonad-intact males was significantly higher than in urethane-NaVP-treated ones (P<0.04). No significant differences were found in analogous female groups. In adenocarcinomas, Ki-67(+) in urethane-treated gonad-intact males was significantly higher than in females and gonadectomized mice of both sexes (P<0.001), and in ovariectomized females was significantly higher than in ovary-intact group (P=0.01). A significantly higher number of Ki-67(+) cells were observed in gonad-intact adenocarcinomas of the urethane-NaVP-treated females compared with the urethane-treated ones (P<0.001). Comparing between urethane-NaVP-treated gonadectomized males and females in adenocarcinomas, determined that Ki-67(+) was significantly lower in females (P=0.005). In adenocarcinomas, Ki-67(+) in urethane-NaVP-treated gonadectomized males and females was significantly lower than in gonad-intact mice of the same sex (P<0.001). In summary, gonadectomy with NaVP treatment decreased Ki-67(+) in adenocarcinomas for mice of both sexes. The results of the present study indicate sex-related differences in mice lung tumorigenesis, and a sex-related effect of NaVP on progression in urethane-induced BALB/c mice lung tumors.

The Effect of Sodium Valproate on the Glioblastoma U87 Cell Line Tumor Development on the Chicken Embryo Chorioallantoic Membrane and on EZH2 and p53 Expression

Literature data support evidences that glioblastoma (GBM) patients experience prolonged survival due to sodium valproate (NaVP) treatment. The study assessed the human GBM cell U87 xenograft studied in the chicken embryo chorioallantoic membrane (CAM) model evaluating NaVP effect on tumor. Three groups of tumors (each n = 10) were studied: nontreated, treated with 4 mM, and treated with 8 mM of NaVP. The majority of tumors without NaVP treatment during tumor growth destroyed the chorionic epithelium, invaded the mesenchyme, and induced angiogenesis. Incidence of tumor formation on CAM without invasion into the mesenchyme was higher when U87 cells were treated with NaVP; the effect significantly increased with NaVP concentration. Treatment with 8 mM of NaVP did not show clear dynamics of tumor growth during 5 days; at the same time, the angiogenesis failed. With a strong staining of EZH2, p53 in tumors without NaVP treatment was found, and NaVP significantly decreased the expression of EZH2- and p53-positive cells; the effect was significantly higher at its 8 mM concentration. NaVP has a function in blocking the growth, invasion, and angiogenesis of tumor in the CAM model; tumor growth interferes with EZH2 and p53 molecular pathways, supporting the NaVP potential in GBM therapy.

The effect of dichloroacetate on male rat thymus and on thymocyte cell cycle

The study aim was to investigate the effect of dichloroacetate (DCA) on thymus and the thymocyte cycle in rats. Wistar male gonad-intact and castrated rats (4–5 weeks) were investigated in the following groups: (1) control; (2) treated with DCA; and (3) treated with the DCA and sodium valproate (NaVP) combination. Rats were treated for 4 weeks with DCA 200 mg/kg/day alone and 300 mg/kg/day of NaVP plus 200 mg/kg/day of DCA (every second week, beginning with NaVP). After the experiment, the thymus was weighted, and the thymus lobe was taken for thymocyte flow cytometry. In gonad-intact rats, the thymus weight of the control was higher than in rats treated with DCA (P <0.001) or with the NaVP–DCA combination (P <0.04); a comparison of thymus weight between DCA- and NaVP–DCA-treated groups revealed a higher thymus weight loss in the DCA-treated group (P <0.03). Flow cytometry shows that DCA treatment increased the percentage of cells in the G2–M phase (P <0.03) and reduced in G1–G0 (P <0.02). The DCA treatment effect was determined only in gonad-intact but not in castrated rats. The authors discuss the possible DCA and NaVP interaction mechanisms.

Off-Label Use of Antipsychotic Agents in Dementia: Evidence for the Revision of the Reimbursement Policy

Background: Harmonized requirements apply for the marketing authorization of medicinal products in the EU Member States. On the contrary, the national legislations on the drug reimbursement are not harmonized. The aim of this study was to find out if they are robust enough to ensure high standards of public health protection with focus on the symptomatic treatment of dementia in the elderly. Methods: A computerized search of authorized therapeutic indications of haloperidol and trihexyphenidyl in the national databases of 8 EU member states and an analysis of the national legislation on reimbursement policies in Lithuania and Latvia was performed. Results: There is a discrepancy in the decisions on the marketing authorization vs the reimbursement in Lithuania and Latvia (reimbursement of haloperidol and trihexyphenidyl for the off-label treatment of dementia). Conclusions: National legislation on the drug reimbursement in Lithuania and Latvia does not provide safeguards for public health at the same level as the marketing authorization does. Absence of a revision of former decisions in the light of new evidence is a critical weakness of the drug reimbursement in Lithuania and Latvia. Reimbursement for the off-label indications may pose a risk to public health.

ABO blood group polymorphism has an impact on prostate, kidney and bladder cancer in association with longevity

The aim of the present study was to assess the ABO blood group polymorphism association with prostate, bladder and kidney cancer, and longevity. The following data groups were analyzed: Prostate cancer (n=2,200), bladder cancer (n=1,530), renal cell cancer (n=2,650), oldest-old (n=166) and blood donors (n=994) groups. The data on the ABO blood type frequency and odds ratio in prostate cancer patients revealed a significantly higher blood group B frequency (P<0.05); the pooled men and women, separate men bladder cancer risk was significantly associated with the blood group B (P<0.04); however, no such association was identified in the female patients. The blood group O was observed to have a significantly decreased risk of bladder cancer for females (P<0.05). No significance for the ABO blood group type in the studied kidney cancer patients was identified. A comparison of the oldest-old and blood donor groups revealed that blood group A was significantly more frequent and blood type B was significantly rarer in the oldest-olds (P<0.05). The results of the present study indicated that blood type B was associated with the risk of prostate and bladder cancer, and could be evaluated as a determinant in the negative assocation with longevity. Blood types O and A may be positive factors for increasing the oldest-old age likelihood. The clustering analysis by the ABO type frequency demonstrated that the oldest-olds comprised a separate cluster of the studied groups.

Sodium Is Not Required for Chloride Efflux via Chloride/Bicarbonate Exchanger from Rat Thymic Lymphocytes

Sodium-dependent Cl−/HCO3 − exchanger acts as a chloride (Cl−) efflux in lymphocytes. Its functional characterization had been described when Cl− efflux was measured upon substituting extracellular sodium (Na+) by N-methyl-D-glucamine (NMDG). For Na+ and Cl− substitution, we have used D-mannitol or NMDG. Thymocytes of male Wistar rats aged 7–9 weeks were used and intracellular Cl− was measured by spectrofluorimetry using MQAE dye in bicarbonate buffers. Chloride efflux was measured in a Cl−-free buffer (Cl− substituted with isethionate acid) and in Na+ and Cl−-free buffer with D-mannitol or with NMDG. The data have shown that Cl− efflux is mediated in the absence of Na+ in a solution containing D-mannitol and is inhibited by H2DIDS. Mathematical modelling has shown that Cl− efflux mathematical model parameters (relative membrane permeability, relative rate of exchanger transition, and exchanger efficacy) were the same in control and in the medium in which Na+ had been substituted by D-mannitol. The net Cl− efflux was completely blocked in the NMDG buffer. The same blockage of Cl− efflux was caused by H2DIDS. The study results allow concluding that Na+ is not required for Cl− efflux via Cl−/HCO3 − exchanger. NMDG in buffers cannot be used for substituting Na+ because NMDG inhibits the exchanger.