Varenicline treatment decreases DNMT1 mRNA expression in lymphocytes of schizophrenic patients who are cigarette smokers

Varenicline for smoking cessation in people with schizophrenia: systematic review and meta-analysis

We performed an updated meta-analysis of randomized double-blind placebo-controlled trials (RCTs) on the effects of varenicline adjuvant therapy for smoking cessation in people with schizophrenia, on the basis of a previous meta-analysis (Tsoi in Cochrane Database Syst Rev 2:CD007253, 2013). We searched PubMed, the Cochrane Library databases, and PsycINFO up to August 1, 2014. RCTs comparing varenicline adjuvant therapy with placebo in schizophrenia were included. The risk ratio (RR), number needed to harm (NNH), and standardized mean differences with its 95% confidence interval (CI) were used. Seven studies (total n = 439), including 6 with only schizophrenia (total n = 352), 1 with both schizophrenia (n = 77) and bipolar disorder (n = 10), were included. Varenicline was not superior to placebo in smoking cessation (RR = 0.79, 95% CI 0.58-1.08, p = 0.14, 5 RCTs, n = 322). Varenicline failed to show its superiority to placebo for overall, positive, negative, and depressive symptoms. Moreover, there was no significant difference in the discontinuation rate due to all causes, clinical deterioration, or side effects between varenicline and placebo. Although varenicline caused less abnormal dreams/nightmares than placebo (RR = 0.47, 95% CI 0.22-0.99, p = 0.05, NNH = not significant, 4 RCTs, n = 288), it caused more nausea (RR = 1.79, 95% CI 1.20-2.67, p = 0.004, NNH = 6, p = 0.004, 6 RCTs, n = 417). We detected no significant difference in suicidal ideation and depression between varenicline and placebo. Our results suggest that although varenicline adjuvant therapy is well tolerated, varenicline is not superior to placebo for smoking cessation in people with schizophrenia. Because of the limited sample sizes of the available studies, future studies will require larger samples to ensure that these findings are generalizable.

A neurochemical basis for an epigenetic vision of psychiatric disorders (1994-2009)

In 1996, Dr. Costa was invited by Prof. Boris Astrachan, Chairman of the Department of Psychiatry at the University of Illinois at Chicago, to direct the research of the "Psychiatric Institute, Department of Psychiatry, School of Medicine, at the University of Illinois at Chicago." He was asked to develop a seminal research program on psychiatric disorders. Viewed in retrospect, Dr. Costa met and surpassed the challenge, as was usual for him. To elucidate the molecular mechanisms whereby nurture (epigenetic factors) and nature (genetic factors) interact to cause major psychiatric disorders was at the center of Dr. Costa's mission for the last 15 years of his research at the Psychiatric Institute. The challenge for Dr. Costa and his colleagues (Auta, Caruncho, Davis, Grayson, Guidotti, Impagnatiello, Kiedrowski, Larson, Manev, Pappas, Pesold, Pinna, Sharma, Smalheiser, Sugaya, Tueting, Veldic [1-111]) had always been to find new ways to prevent and treat psychiatric disorders with pharmacological agents that failed to have major unwanted side effects. In this list, we have quoted the first authors of the papers pertaining to the field of research highlighted in the title. As you know, Dr. Costa was an eclectic scientist and in his 15 years of studies at UIC, he touched many other aspects of neuroscience research that are not discussed in this overview.

Selective α4β2 nicotinic acetylcholine receptor agonists target epigenetic mechanisms in cortical GABAergic neurons

Nicotine improves cognitive performance and attention in both experimental animals and in human subjects, including patients affected by neuropsychiatric disorders. However, the specific molecular mechanisms underlying nicotine-induced behavioral changes remain unclear. We have recently shown in mice that repeated injections of nicotine, which achieve plasma concentrations comparable to those reported in high cigarette smokers, result in an epigenetically induced increase of glutamic acid decarboxylase 67 (GAD(67)) expression. Here we explored the impact of synthetic α(4)β(2) and α(7) nAChR agonists on GABAergic epigenetic parameters. Varenicline (VAR), a high-affinity partial agonist at α(4)β(2) and a lower affinity full agonist at α(7) neuronal nAChR, injected in doses of 1-5 mg/kg/s.c. twice daily for 5 days, elicited a 30-40% decrease of cortical DNA methyltransferase (DNMT)1 mRNA and an increased expression of GAD(67) mRNA and protein. This upregulation of GAD(67) was abolished by the nAChR antagonist mecamylamine. Furthermore, the level of MeCP(2) binding to GAD(67) promoters was significantly reduced following VAR administration. This effect was abolished when VAR was administered with mecamylamine. Similar effects on cortical DNMT1 and GAD(67) expression were obtained after administration of A-85380, an agonist that binds to α(4)β(2) but has negligible affinity for α(3)β(4) or α(7) subtypes containing nAChR. In contrast, PNU-282987, an agonist of the homomeric α(7) nAChR, failed to decrease cortical DNMT1 mRNA or to induce GAD(67) expression. The present study suggests that the α(4)β(2) nAChR agonists may be better suited to control the epigenetic alterations of GABAergic neurons in schizophrenia than the α(7) nAChR agonists.