Jorge Perez

Polymorphism within the promoter of the serotonin transporter gene and antidepressant efficacy of fluvoxamine

Depression with psychotic features has been shown to respond to selective serotonin reuptake inhibitors (SSRIs). The serotonin transporter (5-HTT) is a prime target for SSRIs. A functional polymorphism within the promoter region of the 5-HTT gene, leading to different transcriptional efficiency, was recently reported. We tested the hypothesis that allelic variation of the 5-HTT promoter could be related to the antidepressant response to fluvoxamine and/or augmentation with pindolol (a serotonin autoreceptors antagonist) which has been suggested as an augmentation therapy for nonresponders. One hundred and two inpatients with major depression with psychotic features were randomly assigned to treatment with a fixed dose of fluvoxamine and either placebo or pindolol for 6 weeks. Depression severity was assessed once a week using the Hamilton Depression Rating Scale. Allelic variation in each subject was determined using a PCR-based method. Data were analyzed with a three-way repeated measures analysis of variance. Both homozygotes for the long variant (l/l) of the 5-HTT promoter and heterozygotes (l/s) showed a better response to fluvoxamine than homozygotes for the short variant (s/s). In the group treated with fluvoxamine plus pindolol all the genotypes acted like l/l treated with fluvoxamine alone. Fluvoxamine efficacy in delusional depression seems to be related to allelic variation within the promoter of the 5-HTT gene. Even though other factors may be implicated, genotyping at 5-HTT promoter may represent a promising tool to individualize the pharmacological treatment of depression.

Neurofunctional correlates of vulnerability to psychosis: a systematic review and meta-analysis.

An understanding of the neurobiological correlates of vulnerability to psychosis is fundamental to research on schizophrenia. We systematically reviewed data from studies published from 1992 to 2006 on the neurocognitive correlates (as measured by fMRI) of increased vulnerability to psychosis. We also conducted a meta-analysis of abnormalities of activation in the prefrontal cortex (PFC) in high-risk and first episode subjects, and reviewed neuroimaging studies of high-risk subjects that used PET, SPECT and MRS. Twenty-four original fMRI papers were identified, most of which involved tasks that engaged the PFC. In fMRI studies, vulnerability to psychosis was associated with medium to large effect sizes when prefrontal activation was contrasted with that in controls. Relatives of patients affected with psychosis, the co-twins of patients and subjects with an At Risk Mental State (ARMS) appear to share similar neurocognitive abnormalities. Furthermore, these are qualitatively similar but less severe than those observed in the first episode of illness. These abnormalities have mainly been described in the prefrontal and anterior cingulated cortex, the basal ganglia, hippocampus and cerebellum.

Contribution to characterization of oxidative stress in HIV/AIDS patients

Infection by human immunodeficiency virus (HIV) causes persistent chronic inflammation. Viral Tat protein plays a role in the intracellular increase of reactive oxygen species (ROS) thus increasing apoptotic index, mostly the one mediated by FAS/CD95, and depleting CD4+ T lymphocytes. The aim of this study was to investigate whether there is a relationship between an extensive array of redox status indices (glutathione (GSH), malondialdehyde (MDA), peroxidation potential, total antioxidant status, glutathione peroxidase (GPx), superoxide dismutase (SOD), total hydroperoxide (TH), DNA fragmentation) and relative CD4, CD95, CD38/CD8 T lymphocyte counts in HIV/AIDS patients compared to healthy subjects. Blood samples from 85 HIV/AIDS patients and 40 healthy subjects were tested by spectrophotometric techniques in order to measure oxidative stress indices, and by flow cytometry to quantify T cell subsets. Patients were divided in two groups according to CDC 1993 guidelines. CD95 and CD38 increase paralleled the severity of HIV infection. Both a reduction of GSH levels and an increase in MDA and TH levels were detected in the plasma of HIV+ patients. These patients also showed an increase of DNA fragmentation in lymphocytes as well as a significant (P<0.05) reduction of GPx and an increase in SOD activity in erythrocytes. Relatively to the control group, HIV-infected patients had significantly differences in global indices of total antioxidant status. These results corroborate that substantial oxidative stress occurs during HIV infection. To our knowledge this study is the first relating oxidative stress indices with both CD38/CD8 and CD95 lymphocytes subsets.

How long should pindolol be associated with paroxetine to improve the antidepressant response

A double-blind study was undertaken to investigate the period of treatment with the beta-adrenoreceptor/5-hydroxytryptamine 1A (5-HT1A) antagonist pindolol required to enhance the antidepressant effects of paroxetine. After 1 week of a placebo run-in period, 63 untreated major depressive inpatients were randomly assigned to three different groups. Group 1 received paroxetine (20 mg/day) plus placebo (4 weeks). Group 2 received paroxetine (20 mg/day) plus pindolol (7.5 mg/day) for 1 week and placebo for 3 weeks. Group 3 received both active treatments for the entire duration of the study (4 weeks). Clinical response was defined as a reduction of the score in the Hamilton Rating Scale for Depression (HAM-D) to 8 or below. Also, to preliminarily examine whether beta-adrenoreceptor blockade was involved in the action of pindolol, another group of 10 inpatients was treated in an open-label manner with paroxetine (20 mg/day) plus 50 mg/day of the beta-adrenergic antagonist metoprolol, devoid of significant affinity for 5-HT1A receptors. At endpoint, the incidence of treatment-emergent side effects did not significantly differ among the three groups. After 1 and 2 weeks of treatment, the two groups treated with paroxetine plus pindolol displayed a significantly greater response rate than the group treated with paroxetine plus placebo. At study completion, only the patients treated with pindolol for the entire period showed a significantly greater response rate (p = 0.05). HAM-D score were also significantly lower at endpoint in patients treated with the combination for 4 weeks (p = 0.00003). The group of patients treated with paroxetine and metoprolol exhibited a side-effect profile comparable to that of paroxetine alone. Response rates were also comparable. These findings support the efficacy of pindolol, but not of metoprolol, in accelerating the antidepressant effect of paroxetine and suggest that the administration of pindolol for the entire period of the acute treatment may increase the efficacy of paroxetine.

Electroconvulsive Therapy (ECT) increases serum Brain Derived Neurotrophic Factor (BDNF) in drug resistant depressed patients

Several findings have suggested that the neurotrophin BDNF could contribute to clinical efficacy of antidepressant treatments. The purpose of this study was to analyse if ECT operates a modulation of serum BDNF levels in a sample of drug resistant depressed patients. The results obtained show significantly higher serum levels of BDNF following ECT. More specifically, while no change occurred in the whole sample between T0 (baseline) and T1 (after ECT) (p=0.543) a significant increase has been identified at T2, one month after the end of ECT (p=0.002). However, the BDNF augmentation was evident even between T0 and T1 in a subgroup of patients who has low baseline BDNF levels. Although future researches are needed, the results herein presented show for the first time that ECT is associated with changes in serum BDNF and further support the possible involvement of BDNF in antidepressant therapies.

Impulsivity and bipolar disorder

Impulsivity is frequently associated with bipolar disorder (BD) during manic episodes, but may also be present in euthymic bipolar patients. Aggression is an impulsivity-related behavior also found during manic episodes. The objective of this review is to further clarify the relationship between impulsivity and BD. A search in Medline and Psycinfo databases, combined with a manual search of selected references, was conducted to identify available literature on BD and impulsivity-related features. Although few studies have directly measured impulsivity in BD, available findings suggest that impulsivity is not only state-related, but also a trait component of BD, which could represent a core feature of the illness. Further research exploring the neurobiology of the impulsivity/BD relationship may contribute to elucidate the pathophysiology and to improve the diagnosis and treatment of this severe illness.

Second messenger-regulated protein kinases in the brain: their functional role and the action of antidepressant drugs.

Abstract: Depression has been treated pharmacologically for over three decades, but the views regarding the mechanism of action of antidepressant drugs have registered recently a major change. It was increasingly appreciated that adaptive changes in postreceptor signaling pathways, rather than primary action of drugs on monoamine transporters, metabolic enzymes, and receptors, are connected to therapeutic effect. For some of the various signaling pathways affected by antidepressant treatment, it was shown that protein phosphorylation, which represents an obligate step for most pathways, is markedly affected by long‐term treatment. Changes were reported to be induced in the function of protein kinase C, cyclic AMP‐dependent protein kinase, and calcium/calmodulin‐dependent protein kinase. For two of these kinases (cyclic AMP‐ and calcium/calmodulin‐dependent), the changes have been studied in isolated neuronal compartments (microtubules and presynaptic terminals). Antidepressant treatment activates the two kinases and increases the endogenous phosphorylation of selected substrates (microtubule‐associated protein 2 and synaptotagmin). These modifications may be partly responsible for the changes induced by antidepressants in neurotransmission. The changes in protein phosphorylation induced by long‐term antidepressant treatment may contribute to explain the therapeutic action of antidepressants and suggest new strategies of pharmacological intervention.

Progesterone and estrogens in rat brain: Modulation of GABA (γ-aminobutyric acid) receptor activity

Our data indicate that estrogens and progesterone can regulate the number of GABA receptors (as detected by [3H]muscimol binding assay) in rat brain. Both hormones act in selected areas. The extent of the effect (up to 160% increase) and the number of areas responsive suggest that sex hormones may play a very important role in the regulation of the functions of GABAergic transmission in the central nervous system.

Corticostriatal brain-derived neurotrophic factor dysregulation in adult rats following prenatal stress

Prenatal stress represents a well‐established experimental protocol resembling some features of schizophrenia, including deficits in social interactions, disruption of prepulse inhibition and enhanced response to psychomotor stimulants. In order to evaluate molecular changes that could participate in long‐lasting effects on brain function, we analysed the effects of prenatal stress on the expression of brain‐derived neurotrophic factor (BDNF), an important molecular determinant of synaptic plasticity and cellular homeostasis, in adult male rats under basal conditions as well as in response to a chronic stress. The main finding is that BDNF expression is reduced in the prefrontal cortex and striatum of prenatally stressed rats. Furthermore, when exposed to chronic stress in adulthood, these rats display an altered regulation of BDNF expression in these brain structures, implying that adverse life events during gestation may interfere with the expression and function of this neurotrophin at adulthood in a region‐specific manner. The dysregulation of corticostriatal BDNF expression might thus contribute to permanent alterations in brain functions leading to heightened susceptibility to psychiatric disorders.

Faster onset of action of fluvoxamine in combination with pindolol in the treatment of delusional depression: a controlled study.

This double-blind, controlled study was undertaken to investigate whether the addition of pindolol could improve the therapeutic response to fluvoxamine of depressed patients with psychotic features. After a 1-week placebo run-in period, 72 patients received fluvoxamine 300 mg/day in combination with placebo or pindolol 7.5 mg/day. At study completion, 28 (80%) of 35 patients treated with fluvoxamine plus placebo and 29 (80.5%) of 36 patients treated with fluvoxamine plus pindolol were categorized as responders (reduction of their score on the 21-item Hamilton Rating Scale for Depression to 8 or less and on the Dimension for the Delusional Experience Rating Scale to 0). In the third and fourth weeks, the response rates were significantly superior in the fluvoxamine plus pindolol group (p = 0.0001, p = 0.023, respectively). Treatment response seemed to be unrelated to the demographic and the clinical characteristics recorded. No significant difference was found comparing plasma levels of fluvoxamine between groups, thus excluding a pharmacokinetic interaction. Other than mild nausea and sedation in a few patients, treatments were well tolerated. No medically significant adverse events occurred. Depressed patients with psychotic features who were administered pindolol experienced a more rapid improvement during fluvoxamine treatment. Thus, the combination of fluvoxamine with pindolol may be a useful pharmacologic strategy in the treatment of this disorder. A rapid clinical response in such patients is of relevance in clinical practice as well as in economic fields, given the direct and indirect costs of depression.