Altered diurnal variation of nitric oxide production in patients with panic disorder

Nitric Oxide Synthase Type 1 Methylation Is Associated With White Matter Microstructure in the Corpus Callosum and Greater Panic Disorder Severity Among Panic Disorder Patients

Objectives: Methylation of the neuronal nitric oxide synthase (NOS1/nNOS) gene has recently been identified as a promising biomarker of psychiatric disorders. NOS1 plays an essential role in neurite outgrowth and may thus affect the microstructure development of white matter (WM) in the corpus callosum (CC), which is known to be altered in panic disorder (PD). We examined the relationship between NOS1 methylation, WM tracts in the CC, and symptoms based on this finding.

Methods: Thirty-two patients with PD and 22 healthy controls (HCs) were recruited after age, gender, and the education level were matched. The cell type used was whole-blood DNA, and DNA methylation of NOS1 was measured at 20 CpG sites in the promoter region. Although 25 patients with PD were assessed with the Panic Disorder Severity Scale (PDSS), diffusion tensor imaging (DTI) scans were only collected from 16 participants with PD.

Results: We observed that the PD group showed lower methylation than did the HCs group and positive correlations between the symptom severity of PD and methylation at CpG4 and CpG9. In addition, CpG9 methylation was significantly correlated with the fractional anisotropy (FA) and mean diffusivity (MD) values of the CC and its major components (the genu and the splenium) in the PD group. Furthermore, path analyses showed that CpG9 methylation offers a mediating effect for the association between the MD values of the genu of the CC and PD symptom severity (95% CI = −1.731 to −0.034).

Conclusions: The results suggest that CpG9 methylation leads to atypical development of the genu of the CC, resulting in higher PD symptom severity, adding support for the methylation of NOS1 as a future prognostic indicator of PD.

Alterations of oral microbiota in patients with panic disorder

The main characteristics of panic disorder (PD) include recurrent panic attacks and persistent worry, accompanied by other physical and cognitive symptoms. While recent studies have revealed that gut bacteria play an important role in anxiety and depression, little is known about the relationship between oral microbiota and PD. Therefore, the objective of this study was to explore a possible correlation between oral microbiota and PD. We conducted 16S rRNA sequencing to compare differences in the oral microbiota of patients with PD (n = 26) and healthy controls (n = 40). Patients with PD exhibited higher alpha diversity (abundance and evenness) in their oral microbiota than healthy controls, while analysis of beta diversity revealed that the two groups differed in microbial community composition. Moreover, the relative abundance of 61 genera differed between them. Overall, PD resulted in distinct oral microbial profiles that could be potential diagnostic markers and therapeutic targets.

Candidate SNP Markers of Chronopathologies Are Predicted by a Significant Change in the Affinity of TATA-Binding Protein for Human Gene Promoters

Variations in human genome (e.g., single nucleotide polymorphisms, SNPs) may be associated with hereditary diseases, their complications, comorbidities, and drug responses. Using Web service SNP_TATA_Comparator presented in our previous paper, here we analyzed immediate surroundings of known SNP markers of diseases and identified several candidate SNP markers that can significantly change the affinity of TATA-binding protein for human gene promoters, with circadian consequences. For example, rs572527200 may be related to asthma, where symptoms are circadian (worse at night), and rs367732974 may be associated with heart attacks that are characterized by a circadian preference (early morning). By the same method, we analyzed the 90 bp proximal promoter region of each protein-coding transcript of each human gene of the circadian clock core. This analysis yielded 53 candidate SNP markers, such as rs181985043 (susceptibility to acute Q fever in male patients), rs192518038 (higher risk of a heart attack in patients with diabetes), and rs374778785 (emphysema and lung cancer in smokers). If they are properly validated according to clinical standards, these candidate SNP markers may turn out to be useful for physicians (to select optimal treatment for each patient) and for the general population (to choose a lifestyle preventing possible circadian complications of diseases).

Neuronal nitric oxide synthase (NOS1) and its adaptor, NOS1AP, as a genetic risk factors for psychiatric disorders

Nitric oxide (NO) is a gaseous transmitter produced by nitric oxide synthases (NOSs). The neuronal isoform (NOS-I, encoded by NOS1) is the main source of NO in the central nervous system (CNS). Animal studies suggest that nitrinergic dysregulation may lead to behavioral abnormalities. Unfortunately, the large number of animal studies is not adequately reflected by publications concerning humans. These include post-mortem studies, determination of biomarkers, and genetic association studies. Here, we review the evidence for the role of NO in psychiatric disorders by focusing on the human NOS1 gene as well as biomarker studies. Owing to the complex regulation of NOS1 and the varying function of NOS-I in different brain regions, no simple, unidirectional association is expected. Rather, the 'where, when and how much' of NO formation is decisive. Present data, although still preliminary and partially conflicting, suggest that genetically driven reduced NO signaling in the prefrontal cortex is associated with schizophrenia and cognition. Both NOS1 and its interaction partner NOS1AP have a role therein. Also, reduced NOS1 expression in the striatum determined by a length polymorphism in a NOS1 promoter (NOS1 ex1f-VNTR) goes along with a variety of impulsive behaviors. An association of NOS1 with mood disorders, suggested by animal models, is less clear on the genetic level; however, NO metabolites in blood may serve as biomarkers for major depression and bipolar disorder. As the nitrinergic system comprises a relevant target for pharmacological interventions, further studies are warranted not only to elucidate the pathophysiology of mental disorders, but also to evaluate NO function as a biomarker.

Biological understanding of the cardiovascular risk associated with major depression and panic disorder is important

INTRODUCTION

Panic disorder (PD) and major depressive disorders (MDD) are serious mental disorders but the mechanisms underlying the pathophysiology are poorly understood. Nitric oxide (NO) is a gas considered to play an important role in mediating anxiety and stress response and is synthesised from nitric oxide synthase (NOS). The endothelial isoform (eNOS) has been found also in platelets. Homocysteine (Hcy) is an amino acid which naturally occurs in the human body. Elevated levels are linked to increased risk of cardiovascular, neurological and psychiatric diseases. In this study we aimed to evaluate NO, platelet aggregation and Hcy levels in PD and MDD patients.

MATERIALS AND METHODS

Nineteen PD and 18 MDD patients participated in this study. NO levels were measured spectrophotometrically, platelet aggregation levels were measured in an aggregometer and Hcy levels were measured by HPLC.

RESULTS

NO levels were significantly lower in patients with MDD and PD than in control subjects (P < 0.05). Hcy and platelet aggregation levels were significantly higher in patients with MDD and PD than in control subjects (P < 0.05).

CONCLUSION

Further more detailed studies are needed to find out the effects of drugs on these parameters or to disclose the exact mechanism underlying the alteration of these parameters.

Plasma nitrate levels and flow-mediated vasodilation in untreated major depression

OBJECTIVE

Findings from several studies have revealed that major depression is associated with an increased cardiovascular risk. The physiopathologic mechanisms of this association remain unclear, although recently, it has been hypothesized that a decreased production of nitric oxide could be a potential contributor to vascular dysfunction in depressive patients. The objective of this study was to evaluate nitric oxide production and vascular endothelial function in treatment-naive young healthy adults with a first episode of major depression.

METHODS

A case-control study in 50 treatment-naive young adults with a first episode of major depression and 50 healthy control subjects was conducted. Plasma levels of nitric oxide metabolites (nitrates/nitrites) were determined using a colorimetric assay based on Griess reaction. Endothelial function was assessed by flow-mediated vasodilation measurements after reactive hyperemia.

RESULTS

The mean age of the depressed patients was 22.6 (standard deviation [SD], 4.6) years, whereas the controls were 23.4 (SD, 4.8) years. Sixteen men (32%) and 34 women (68%) were included in each group. The plasma nitrite/nitrate concentrations were significantly lower in depressive subjects compared with healthy controls (17.5 [SD, 4.9] μmol/L versus 21.6 [SD, 7.0] μmol/L, p < .001); however, flow-mediated vasodilation values were similar in both groups (13.1% [SD, 4.3%] versus 12.1% [SD, 5.0%], p = .10).

CONCLUSIONS

Decreased plasma concentrations of nitric oxide metabolites are not associated with vascular endothelial dysfunction in young subjects with a first episode of major depression. Reduced nitrate/nitrite levels could reflect a decreased nitric oxide production in the central nervous system of depressed subjects. Further studies are needed to confirm this hypothesis.

Body temperature in patients with panic disorder treated with escitalopram

The aim of the study was to investigate the influence of escitalopram on peripheral body temperature (PBT) in panic disorder. In a 4 week case-control study (N = 12 female patients; N = 12 matched healthy controls), the daytime PBT declined compared to night time PBT in patients. The prospective relationship between PBT and panic disorder shows a decline of daytime PBT compared to the night time PBT in panic disorder from week 2 of treatment with escitalopram onwards. The effect of escitalopram on daytime PBT may have occurred through an activation of the sympathetic system.

Twenty-four-hour variation of L-arginine/nitric oxide/cyclic guanosine monophosphate pathway demonstrated by the mouse visceral pain model

The L-arginine/nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) pathway is known to be involved in central and peripheral nociceptive processes. This study evaluated the rhythmic pattern of the L-arginine/NO/cGMP pathway using the mouse visceral pain model. Experiments were performed at six different times (1, 5, 9, 13, 17, and 21 h after light on) per day in male mice synchronized to a 12 h:12 h light-dark cycle. Animals were injected s.c. with saline, 2 mg/kg L-arginine (a NO precursor), 75 mg/kg L-N(G)-nitroarginine methyl ester (L-NAME, a NOS inhibitor), 40 mg/kg methylene blue (a soluble guanylyl cyclase and/or NOS inhibitor), or 0.1 mg/kg sodium nitroprusside (a nonenzymatic NO donor) 15 min before counting 2.5 mg/kg (i.p.) p-benzoquinone (PBQ)-induced abdominal constrictions for 15 min. Blood samples were collected after the test, and the nitrite concentration was determined in serum samples. L-arginine or L-NAME caused both antinociception and nociception, depending on the circadian time of their injection. The analgesic effect of methylene blue or sodium nitroprusside exhibited significant biological time-dependent differences in PBQ-induced abdominal constrictions. Serum nitrite levels also displayed a significant 24 h variation in mice injected with PBQ, L-NAME, methylene blue, or sodium nitroprusside, but not saline or L-arginine. These results suggest that components of L-arginine/NO/cGMP pathway exhibit biological time-dependent effects on visceral nociceptive process.

Panic disorder, cardiac diagnosis and emergency department utilization in an epidemiologic community sample

OBJECTIVE

We examined the association between panic disorder (PD), physician-diagnosed cardiac disease (CD), and the interaction of these variables in relation to health care utilization, as measured by emergency department (ED) visitations, in an epidemiologic sample.

METHODS

Subjects were identified from the National Epidemiologic Survey on Alcohol and Related Conditions, a nationally representative sample of 43,093 adult respondents from the United States who completed face-to-face computer-assisted structured clinical interviews.

RESULTS

Among patients with CD, the 12-month prevalence of PD (6.0%; 613/10,239) was significantly higher than that among non-CD subjects (3.4%; 1106/32,854; adjusted odds ratio=2.4; 95% confidence interval=2.2-2.7). CD patients with PD had a significantly greater prevalence of angina, tachycardia and alcohol use disorders as compared with PD-negative patients. PD-positive patients reported significantly greater mean 12-month ED visits (1.2) as compared with the PD-negative patients (0.6; P<.001). PD and tachycardia were found to have a significant interaction effect on ED visits for males (F=25.1; df=1,7; P<.001) but not for females (F=1.2; df=1,7; P=.28), with age, income, race and alcohol use included as covariates.

CONCLUSIONS

Epidemiological data support a relationship between PD and CD that impacts ED utilization. These findings have potential implications for medical, psychiatric and ED-based screening and interventions.