miR-181a/b downregulation exerts a protective action on mitochondrial disease models.

Mitochondrial diseases (MDs) are a heterogeneous group of devastating and often fatal disorders due to defective oxidative phosphorylation. Despite the recent advances in mitochondrial medicine, effective therapies are still not available for these conditions. Here, we demonstrate that the microRNAs miR-181a and miR-181b (miR-181a/b) regulate key genes involved in mitochondrial biogenesis and function and that downregulation of these miRNAs enhances mitochondrial turnover in the retina through the coordinated activation of mitochondrial biogenesis and mitophagy. We thus tested the effect of miR-181a/b inactivation in different animal models of MDs, such as microphthalmia with linear skin lesions and Leber's hereditary optic neuropathy. We found that miR-181a/b downregulation strongly protects retinal neurons from cell death and significantly ameliorates the disease phenotype in all tested models. Altogether, our results demonstrate that miR-181a/b regulate mitochondrial homeostasis and that these miRNAs may be effective gene-independent therapeutic targets for MDs characterized by neuronal degeneration.

A(2A) adenosine receptor binding parameters in platelets from patients affected by pathological gambling.

BACKGROUND/AIMS: A structural and functional interaction between A(2A) adenosine receptors and D(2) dopamine receptors has been implicated in the pathophysiology of impulse control disorders. The aim of this study was to use platelet membranes to assess A(2A) adenosine receptor affinity and density in patients affected by pathological gambling (PG; which is classified as a specific impulse control disorder) with respect to those of control subjects. METHODS: Twelve drug-free PG patients and 12 age- and sex-matched healthy controls were enrolled in the study. PG was diagnosed according to the Structured Clinical Interview for DSM-IV - Patient Version 2.0 and the South Oaks Gambling Screen. A(2A) adenosine receptor binding parameters were evaluated using a [(3)H]ZM(241385) binding assay; affinity and density (B(max)) were determined by means of saturation binding studies with platelet membranes. RESULTS: The A(2A) adenosine receptor binding affinity was found to be significantly higher in patients affected by PG than in healthy subjects; in contrast, no significant differences in B(max) were observed between the 2 groups. CONCLUSIONS: The elevated A(2A) adenosine receptor binding affinity in platelets from PG patients with respect to control subjects demonstrates for the first time a change in adenosine receptor parameters, and it suggests the involvement of the adenosine system in this pathology. The previously demonstrated hyperactivity of the dopamine system in PG may modulate the A(2A) adenosine receptor, supporting a role for this receptor as a peripheral marker of dopamine dysfunction. Because it is not possible to directly measure the D(2) dopamine receptor in human platelets, these data are particularly relevant to the detection of dopamine dysfunction.

Trazodone effects on [H]-paroxetine and alpha(2)-adrenoreceptors in platelets of patients with major depression.

Trazodone is an antidepressant which behaves as a selective 5-HT(2) antagonist and 5-HT reuptake inhibitor. The lack of information on its effects in vivo prompted us to evaluate alpha(2)-adrenoceptors by means of the specific binding of [(3)H]-rauwolscine, and the 5-HT transporter (SERT) by means of the binding of [(3)H]-paroxetine ([(3)H]-Par), in platelets of depressed patients, before and after one month of treatment with trazodone (75-300 mg/day). Twenty-five outpatients of both sexes with a diagnosis of major depression, as assessed by the Structured Clinical Interview for DSM IV, were included in the study. Depressive symptoms were evaluated by means of the Hamilton Rating Scale for Depression: the total score (mean +/- SD) was 20 +/- 6 at baseline (t(0)) and 7 +/- 4 after one month of treatment (t(1)). Platelet membranes, [(3)H]- rauwolscine and [(3)H]-Par bindings were carried out according to standardized protocols. The results showed that the B(max) values of [(3)H]-Par were statistically lower at t(1) than at t(0) (733 +/- 30 vs 1471 +/- 99, P < 0.001), while the K(d) and the [(3)H]-rauwolscine binding parameters remained unchanged. The findings of this study suggest that in vivo trazodone modifies the number of the SERT proteins and that, perhaps, most of its antidepressant properties are related to this activity.

Differential substance abuse patterns distribute according to gender in heroin addicts.

This study attempts to analyse potential gender differences among a group of heroin addicts seeking treatment at a university-based medical centre. The central modality of treatment at this centre is the use of methadone maintenance. Among those patients entering this program there seems to be an emerging pattern of males who tend to use heroin as their opiate of choice, and are more likely to combine it with cannabis, while females are more likely to use to street methadone, with adjunctive use of ketamine, benzodiazepines, hypnotic drugs and/or amphetamines. Women are at higher risk of abusing opioids through a pathway of initial prescription painkiller use, and later to resort to street methadone to cope with prescription pain killer addiction. This latter pattern seems to result in an increased risk for fatal accidental overdoses. The use of these longer-acting agents in women may be influenced by psychosocial and hormonal factors.

Impulsivity, gender, and the platelet serotonin transporter in healthy subjects.

The present study explored the possible relationships between impulsivity, gender, and a peripheral serotonergic marker, the platelet serotonin (5-HT) transporter (SERT), in a group of 32 healthy subjects. The impulsivity was measured by means of the Barratt Impulsivity Scale, version 11 (BIS-11), a widely used self-report questionnaire, and the platelet SERT was evaluated by means of the specific binding of (3)H-paroxetine ((3)H-Par) to platelet membranes, according to standardized protocols. The results showed that women had a higher BIS-11 total score than men, and also higher scores of two factors of the same scale: the motor impulsivity and the cognitive complexity. The analysis of the correlations revealed that the density of the SERT proteins, as measured by the maximum binding capacity (B(max)) of (3)H-Par, was significantly and positively related to the cognitive complexity factor, but only in men. Men showed also a significant and negative correlation with the dissociation constant, Kd, of ((3)H-Par) binding, and the motor impulsivity factor. These findings suggest that women are generally more impulsive than men, but that the 5-HT system is more involved in the impulsivity of men than in that of women.

Effectiveness of long-term augmentation with citalopram to clomipramine in treatment-resistant OCD patients.

INTRODUCTION: The high percentage (between 40% and 60%) of resistance to first-line drugs, such as clomipramine or selective serotonin reuptake inhibitors, is a major problem in the pharmacologic management of obsessive-compulsive disorder (OCD). In these cases, different strategies have been employed with controversial outcomes. The meager information available on the association of two serotonergic drugs prompted us to explore the possible effectiveness and tolerability of citalopram+clomipramine in resistant OCD patients. METHODS: Twenty outpatients with a Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition diagnosis of OCD, who had failed to respond to at least two trials with a selective serotonin reuptake inhibitor and were currently taking clomipramine at different doses, were administered citalopram at a maximum dose of 60 mg/day. The clinical assessment was carried out at baseline (t0) and at the 4th (t1), 12th (t2), 24th (t3), 36th (t4), and 48th (t5) week by means of the Yale-Brown Obsessive Compulsive Scale, Hamilton Rating Scale for Depression, Clinical Global Impression scale, and the Dosage Record and Treatment Emergent Symptom Scale. The response was defined as a 35% decrease of the Yale-Brown Obsessive-Compulsive Scale total score. RESULTS: The results showed that approximately 50% of the patients improved significantly after 1 month of this regimen and after 1 year of treatment. CONCLUSION: This study, although carried out in a small sample and in an open fashion, represents one of the few experiences with the association of two serotonergic compounds in resistant OCD and confirms its potential usefulness and good tolerability profile. Controlled research on this association in OCD is recommended.

Decreased density of the platelet serotonin transporter in pathological gamblers.

BACKGROUND/AIMS: The aim of this study was to investigate the serotonin transporter (SERT), by means of the 3H-paroxetine ([3H]-Par) binding to platelet membranes, in patients affected by pathological gambling (PG), as compared with a similar group of healthy control subjects. METHODS: Seventeen PG patients were selected amongst those who were drug-free and at the first psychiatric interview in a Department of Addiction. The diagnosis was assessed according to DSM-IV criteria and PG severity was measured by means of the South Oaks Gambling Screen. The platelet [3H]-Par binding was carried out according to a standardized method. The binding parameters, the maximum binding capacity (B(max)) and the dissociation constant (K(d)), were obtained by means of the Scatchard analysis. RESULTS: The B(max) values of PG patients were significantly lower than that of healthy subjects, while the K(d) values were not different in the two groups. No significant effect of age, sex or psychiatric comorbidity on B(max) or K(d) was observed; there were also no correlations between clinical and biological variables. CONCLUSIONS: PG patients showed a dysfunction at the level of the platelet SERT that would suggest the involvement of the 5-HT system in this condition.

Executive function abnormalities in pathological gamblers.

BACKGROUND: Pathological gambling (PG) is an impulse control disorder characterized by persistent and maladaptive gambling behaviors with disruptive consequences for familial, occupational and social functions. The pathophysiology of PG is still unclear, but it is hypothesized that it might include environmental factors coupled with a genetic vulnerability and dysfunctions of different neurotransmitters and selected brain areas. Our study aimed to evaluate a group of patients suffering from PG by means of some neuropsychological tests in order to explore the brain areas related to the disorder. METHODS: Twenty outpatients (15 men, 5 women), with a diagnosis of PG according to DSM-IV criteria, were included in the study and evaluated with a battery of neuropsychological tests: the Wisconsin Card Sorting Test (WCST), the Wechsler Memory Scale revised (WMS-R) and the Verbal Associative Fluency Test (FAS). The results obtained in the patients were compared with normative values of matched healthy control subjects. RESULTS: The PG patients showed alterations at the WCST only, in particular they had a great difficulty in finding alternative methods of problem-solving and showed a decrease, rather than an increase, in efficiency, as they progressed through the consecutive phases of the test. The mean scores of the other tests were within the normal range. CONCLUSION: Our findings showed that patients affected by PG, in spite of normal intellectual, linguistic and visual-spatial abilities, had abnormalities emerging from the WCST, in particular they could not learn from their mistakes and look for alternative solutions. Our results would seem to confirm an altered functioning of the prefrontal areas which might provoke a sort of cognitive "rigidity" that might predispose to the development of impulsive and/or compulsive behaviors, such as those typical of PG.