Arianna De Lalla

Nimodipine: drug pharmacokinetics and plasma adenosine levels in patients affected by cerebral ischemia.

Nimodipine is a dihydropyridine calcium channel blocker used in the treatment of ischemic damage in subarachnoid hemorrhage. Recent investigations have shown that it is able to inhibit adenosine transport in human red blood cells and parietal cortex neurons. In this study we investigated the pharmacokinetics of nimodipine and the effect on plasma adenosine levels in patients affected by cerebral ischemia.

Experimental Model of Short-Time Exercise-Induced Preconditioning in POAD Patients:

Regular physical exercise improves walking performance in patients affected with periph eral obliterative arterial disease (POAD). The mechanisms underlying the phenomenon are still controversial. In order to verify the hypothesis that physical conditioning of lower limbs on a treadmill and ischemic preconditioning of the heart could share some biolog ical aspects, 14 POAD subjects underwent a training program on the treadmill consisting of five repeated submaximal exercises at five-minute and two-hour intervals preceding the maximal tolerance test. Moreover, a protocol with two daily submaximal walking exercises over one week was also performed. Pain-free and total walking distance were measured before and after they performed the program. Moreover, plasma levels of adenosine and adenosine triphosphate (ATP) were measured and polymorphonuclear (PMN) leukocyte activity was studied together with rheologic parameters. Pain-free distance was prolonged by 15.4% and 14.3%, and total distance was prolonged by 23.1% and 26.9%, in the exercises with five-minute and two-hour intervals, respectively. After one week of daily exercises, the onset of pain and the end of the test were delayed by 24% and 43.7%, respectively. An improvement in blood rheology and a reduced PMN reactivity were also observed with the three protocols, associated with an increase in plasma levels of adenosine and ATP. Similarly to ischemic preconditioning in the heart, the possibility is suggested that an adenosine-mediated mechanism may contribute to the development of physical condi tioning in treadmill-trained POAD patients.

Sympathetic overactivity and plasma leptin levels in Rett syndrome

Rett syndrome (RTT) is a severe developmental-neurological disorder, characterized by profound and progressive loss of intellectual functioning, occurring after a period (of at least 6 months) of normal development with classic stereotype hand movements, gait ataxia, jerky truncal ataxia, deceleration of brain and body organ growth and cardiac dysautonomia. Pathogenesis of sympathetic overactivity in RTT is unknown, but a previous study observed increased plasma leptin levels in Rett girls and it is well known the role of leptin in the regulation of sympathetic nervous system activity. Aim of our study is to evaluate a relationship between plasma leptin levels and sympathetic activity in RTT. Thirty-two female patients (12.1+/-6.3 years), affected by RTT were enrolled in the study. In all the subjects, we analyzed heart rate variability, QT corrected interval and plasma leptin levels. A significant correlation was found between plasma leptin levels and LF/HF (expression of sympatho-vagal balance) (Spearman r=0.44, p=0.001). There is also a significant negative correlation between HF component (expression of vagal activity) and plasma leptin levels (Spearman r=-0.037, p=0.03) and a positive correlation between LF component and plasma leptin levels (Spearman r=0.047, p=0.01). These results show that in RTT higher plasma leptin levels appear to be associated with sympathetic overactivity, suggesting a role for leptin in cardiac dysautonomia.

Variations of plasma leptin and adiponectin levels in autistic patients.

Autism is a neurodevelopmental disorder with pathogenesis not completely understood. Although a genetic origin has been recognized, it has been hypothesized a role for environmental factors, immune dysfunctions, and alterations of neurotransmitter systems. In young autistic patients we investigated plasma leptin and adiponectin levels over a year period. Thirty-five patients, mean age at the basal time 14.1+/-5.4 years, were enrolled. Controls were 35 healthy subjects, sex and age matched. Blood samples were withdrawn in the morning at the baseline and 1 year after. In patients leptin concentrations significantly increased, while adiponectin did not significantly change. Leptin values in patients were significantly higher than those found in controls at each time; adiponectin values did not differ at each time between patients and controls. Since patients were not obese, we could hypothesize that leptin might participate to clinical manifestations other than weight balance. The role of adiponectin in autism is still debatable.

Plasma Levels of Asymmetric Dimethylarginine in Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarct and Leukoencephalopathy

Background: Asymmetric dimethylarginine (ADMA) is a marker of endothelial dysfunction and a new independent risk factor for adverse cerebrovascular events in small vessel disease. Conversely, L-arginine (LARG) may have a protective role. Methods: To assess ADMA, LARG levels and LARG/ADMA ratio in 16 patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and normal controls, and to look for possible correlations with white matter changes. Plasma levels of ADMA and LARG were assayed by high-performance liquid chromatography in all subjects. The overall T1 and T2 lesion load was obtained from brain MRI of patients with CADASIL. Results: ADMA plasma concentrations (1.5 ± 2.0 µM) were significantly higher (p < 0.05) in CADASIL patients than in controls (0.35 ± 0.075 µM). Analyzing only CADASIL subjects, an inverse borderline-significant correlation was found between LARG/ADMA (190 ± 20) and T2-weighted lesion volumes (57.9 ± 46.5; r = –0.578, p = 0.024). Conclusion: Our results may indicate the possible coexistence of endothelial dysfunction in CADASIL patients, broadening the range of potentially pathogenetic mechanisms in this disease and providing insights for future therapeutic strategies.

Activity of citalopram on adenosine and serotonin circulating levels in depressed patients.

Abstract: Citalopram is a selective serotonin reuptake inhibitor used in the treatment of depression. Recent investigations have shown that it reduces in rat brain the release of excitatory amino neurotransmitters acid glutamate and aspartate by the involvement of the inhibitory neuromodulator adenosine. In this study, we described citalopram and serotonin levels in plasma and platelets, as well as plasma adenosine levels, in depressive patients during acute and chronic administration of citalopram. Twelve patients affected by Major Depression (DSM-IV) received a single oral dose of citalopram in the morning, 5 mg in the first 5 days, 10 mg from the 6th to the 10th day, and 20 mg from the 11th to the 40th day. Blood samples for citalopram, serotonin, and adenosine were collected at Time 0 and 4, 12 and 24 hours after drug administration on the first day of citalopram 5 mg, and on the first and the last day of citalopram 20 mg. Citalopram, serotonin, and adenosine concentrations in plasma increased after citalopram administration, and the highest levels were observed on the last day of treatment. Citalopram was detectable in platelets with concentrations showing a time variation similar to plasma values. Serotonin levels in platelets decreased after drug administration, reaching the lowest values on the last day of treatment.

Pharmacokinetics and pharmacodynamics of neutrophil‐associated ciprofloxacin in humans

To study the possibility that the penetration of the antibiotic ciprofloxacin into polymorphonuclear leukocytes (PMN) may be associated with some changes in cell reactivity.

Plasma Catecholamine Levels after Fluoxetine Treatment in Depressive Patients

It is known that selective serotonin reuptake inhibitors, widely used as antidepressive drugs, act by inhibiting the cell reuptake of serotonin, but their effect on the catecholaminergic system is not yet completely understood. In this study, we investigated plasma concentrations of norepinephrine, epinephrine and dopamine after acute and chronic administration of fluoxetine in depressive patients. Twelve patients affected by major depression received a single oral dose of fluoxetine in the morning, 5 mg in the first 5 days, 10 mg from the 6th to the 10th day and 20 mg from the 11th to the 40th day. Twelve healthy subjects received a placebo under identical testing procedures. Blood samples were collected at baseline and 7, 10 and 24 h after drug administration on the 1st day of fluoxetine administration at a dose of 5 mg, and on the 1st and the 30th day of fluoxetine administration at a dose of 20 mg (days 11 and 40 of treatment, respectively). We found that plasma norepinephrine, epinephrine and dopamine levels significantly increased after acute and chronic treatment (p < 0.001), reaching the highest concentrations on the last day. No significant changes of these parameters were observed in control patients.

Topiramate effects on plasma serotonin levels in children with epilepsy

Topiramate (TPM) is a new, effective and safe antiepileptic drug. TPM is also effective in treating a wide spectrum of conditions such as eating disorders and related anomalies, bulimia nervosa and other conditions in which serotonin (5-hydroxytryptamine, 5-HT) is involved pathogenetically. Plasma serotonin mainly derives from blood platelets, which represent a valid model of serotoninergic neurons. We measured plasma 5-HT levels in 12 children affected by epilepsy who underwent TPM therapy. Inclusion criteria were (i) age range 2-12 years, (ii) weight greater than 12 kg, (iii) no more than one antiepileptic drug used when TPM therapy was instituted, and (iv) a minimum study period of 3 months. After a mean period of 3 months of TPM treatment, a significant increase in mean plasma serotonin levels was observed with respect to the basal levels and those of a control group. There were no significant correlations between the changes in serotonin concentrations and the antiepileptic efficacy or doses of TPM used. TPM may influence serotonin metabolism in children affected by epilepsy. Further studies are needed to establish whether these serotonin plasma changes represent an epiphenomenon or indicate direct effects of TPM on the serotoninergic system.