Dariusz Andrzejczak

Cytotoxic Activity of Pyrovalerone Derivatives, an Emerging Group of Psychostimulant Designer Cathinones.

The growing popularity of novel psychoactive substances (NPS) has aroused the concerns of public health specialists. The pyrovalerone derivatives are a branch of synthetic cathinones, a very popular group of psychostimulant NPS. Despite numerous case reports of fatal intoxications, little is known about the cytotoxicity of these substances. Therefore, this study was aimed to evaluate the toxic properties of pyrovalerone, its highly prevalent derivative 3,4-methylenedioxypyrovalerone (3,4-MDPV) with its two major metabolites (catechol-MDPV and methylcatechol-MDPV) and the structural isomer 2,3-MDPV, together with newer members of the group, i.e., α-pyrrolidinovalerothiophenone (α-PVT) and α-pyrrolidinooctanophenone (PV9), using model human cell lines for neurons (SH-SY5Y), hepatocytes (Hep G2), and upper airway epithelium (RPMI 2650). We found that the first generation pyrovalerones (pyrovalerone, 3,4-MDPV, and 2,3-MDPV) produced a modest decrease of mitochondrial activity in the three examined cell lines, but were active in lower concentrations than methamphetamine used as a reference psychostimulant compound. Since catechol-MDPV displayed greater toxic potential than the parent compound, we suggest that the toxicity of 3,4-MDPV could be attributed to activity of this metabolite. Strikingly, the two new generation pyrovalerones, α-PVT and PV9, seem to be the most potent cytotoxic compounds: both induced highly pronounced mitochondrial dysfunction; the latter also demonstrated significant damage to cell membranes. The reported in vitro toxic activity of pyrovalerone cathinones against different cell types reinforces existing concerns regarding the health risks associated with the intake of these drugs.

The effects of celiprolol on serum concentrations of proinflammatory cytokines in hypertensive (SHR) and normotensive (WKY) rats

BACKGROUND A growing body of evidence suggests that some cardiovascular drugs could modulate the level of proinflammatory cytokines. Therefore, the aim of the present study was to investigate whether celiprolol, a third generation β-adrenoceptor blocker, affects lipopolysaccharide (LPS)-induced serum concentrations of TNF-α, IL-1β, IL-6 in normotensive (WKY) and spontaneously hypertensive (SHR) rats. METHODS Celiprolol (150 mgkg(-1)) or vehicle was administered by gavage once daily for 21 days. Arterial blood pressure was measured in conscious rats, using the tail-cuff method. Serum concentrations of proinflammatory cytokines were measured with enzyme-linked immunosorbent assay kits. Additionally, plasma concentrations of total cholesterol, HDL-cholesterol and triglycerides were evaluated. RESULTS In normotensive WKY rats celiprolol did not affect heart rate, blood pressure, or the serum concentrations of triglycerides, total cholesterol or HDL-cholesterol. In hypertensive animals the drug decreased lipid parameters, increased diastolic and mean blood pressure after the first week of administration, and produced a small but significant decrease in heart rate after the first two weeks of the treatment. In both groups of animals, celiprolol decreased LPS-stimulated serum concentration of IL-6 but did not affect levels of TNF-α and IL-1β. CONCLUSIONS It is suggested that the IL-6-modulating properties of celiprolol could provide additional value to the therapeutic effectiveness of the drug in the treatment of hypertension.

Does nebivolol influence serum concentrations of proinflammatory cytokines in hypertensive (SHR) and normotensive (WKY) rats

A growing body of evidence suggests that some drugs used in cardiovascular diseases may modulate the level of proinflammatory cytokines. In the present study we examined whether nebivolol, a third generation beta-adrenergic blocker, influences lipopolysaccharide (LPS)-induced serum concentrations of TNF-alpha, IL-1beta, and IL-6 in normotensive (WKY) and spontaneously hypertensive rats (SHR). Nebivolol (5 mg/kg and 10 mg/kg) or vehicle were administered by gavage once a day for 21 days. The drug (5 mg/kg and 10 mg/kg) did not modify LPS-stimulated serum concentrations of TNF-alpha, IL-1beta and IL-6 in normotensive or hypertensive rats and did not affect the total cholesterol and HDL cholesterol level. Nebivolol, at the dose of 10 mg/kg, significantly increased the triglyceride concentration in SHR only. The results were accompanied by a statistically significant decrease in systolic, diastolic and mean blood pressure after 21 days of both of the drug doses. In hypertensive and normotensive rats, nebivolol had a hypotensive activity and neutral effect on lipid profile. In our in vivo model, the immunomodulating effect of the drug was not significant and probably did not depend on hemodynamic action.

The effects of topiramate on lipopolysaccharide (LPS)-induced proinflammatory cytokine release from primary rat microglial cell cultures

A growing body of evidence suggests that inflammatory processes and activation of glial cells could contribute to seizures and epileptogenesis. In various animal studies on epilepsy, proinflammatory cytokines have been demonstrated to exert a proconvulsive activity. On the other hand, it is suggested that antiepileptic drugs could modulate immune system activity. The aim of the present study was to investigate whether topiramate, a new generation antiepileptic drug with a complex mechanism of action, could affect the lipopolysaccharide (LPS)-induced release of TNF-α, IL-1β and IL-6 from primary rat microglial cell cultures. Proinflammatory cytokines were measured in supernatants of primary rat microglial cell culture with enzyme-linked immunosorbent assay kits. Additionally, the effect of the drug on LPS-evoked changes in mitochondrial metabolic activity was evaluated with the aid of the MTT test. Topiramate (1, 10, 100μg/ml; 24h incubation) produced a statistically significant decrease in LPS-stimulated IL-1β and IL-6 levels from primary rat microglial cells in a concentration-dependent manner. The drug used at a concentration of 100μg/ml also significantly suppressed TNF-α release. Incubation of microglial cells with topiramate for 24h prevented the LPS-induced increase in their mitochondrial activity. It is suggested that the anti-cytokine action of topiramate could provide an additional mechanism in its antiepileptic activity.

Effects of the new generation α-pyrrolidinophenones on spontaneous locomotor activities in mice, and on extracellular dopamine and serotonin levels in the mouse striatum

PurposePyrovalerone derivatives (α-pyrrolidinophenones) form a distinct branch of synthetic cathinones, a popular group of novel psychoactive substances, and exert strong psychostimulatory effects resulting from their high potency to inhibit dopamine (DA) and norepinephrine transporters, with negligible activity at the serotonin (5-HT) transporter. In contrast to the old generation α-pyrrolidinophenones, 3,4-MDPV and α-PVP, there is limited data on the pharmacology and toxicology of the novel analogs. Therefore, the present study assesses the in vivo effects of two new pyrovalerones, PV8 and PV9, along with those of α-PVP, on spontaneous locomotor activities of mice and extracellular DA and 5-HT levels in the mouse striatum.MethodsSpontaneous locomotor activity was measured using Opto-Varimex Auto-Track. Effects of tested compounds on extracellular levels of DA and 5-HT in the striatum were studied by an in vivo microdialysis technique; their concentrations in dialysate fractions were analyzed by high-performance liquid chromatography with electrochemical detection.Resultsα-PVP, PV8 and PV9 stimulated mice locomotor activity (an effect being blocked by D1-dopamine receptor antagonist, SCH 23390), and increased extracellular levels of DA and 5-HT in the striatum. Observed effects depend on dose, time and compound under investigation, with α-PVP being more potent than PV8 and PV9. When used at the same dose, the pyrovalerones produced effects significantly weaker than a model, old generation psychostimulant, methamphetamine.ConclusionsEnhancement of dopaminergic neurotransmission plays a dominant role in the psychomotor stimulation caused by α-PVP, PV8 and PV9. Extending an aliphatic side chain beyond a certain point leads to the decrease in their potency in vivo.

Cytotoxicity of α-Pyrrolidinophenones: an Impact of α-Aliphatic Side-chain Length and Changes in the Plasma Membrane Fluidity

Pyrovalerone derivatives (α-pyrrolidinophenones) form a branch of synthetic cathinones, a second most prominent group of novel psychoactive substances. Although the toxicity of 3,4-MDPV, a progenitor of the α-pyrrolidinophenones, is well described, little is known of the potential cytotoxicity of the new members of this group entering the recreational drug market each year. The present study assesses the cytotoxicity of members of the α-pyrrolidinophenone group, i.e., α-PVP, its longer side-chain derivatives PV8 and PV9, and their 4-fluoro- and 4-methoxy-analogs, against model cell lines for the nervous system (SH-SY5Y), liver (Hep G2) and upper airway epithelium (RPMI 2650), and cardiomyocytes (H9C2(2-1)). Additionally, an impact of pyrovalerones on the fluidity of the plasma membrane, as the potential mechanism of their cytotoxicity, was examined. The longer side-chain α-pyrrolidinophenones and their fluoro- and methoxy-analogs produce more pronounced maximal cytotoxicity, with regard to mitochondrial activity and cell membrane integrity, than the five-carbon α-PVP and its substituted derivatives. The report demonstrates, for the first time, that changes of fluidity of the interior part of plasma membrane contribute to the cytotoxicity of pyrovalerone derivatives, in addition to the previously reported mechanisms. Taking into consideration our previous findings that PV8 and PV9 produce weaker psychostimulatory effects than α-PVP, the higher cytotoxicity of the new generation of pyrovalerones can pose a serious threat to abusers, as it is possible that longer-chain compounds may be taken in higher doses to obtain similar levels of stimulation.