Lower paraoxonase 1 activity in Tunisian bipolar I patients

Lipid Biomarker Research in Bipolar Disorder: A Scoping Review of Trends, Challenges, and Future Directions

Bipolar disorder (BD) is a disabling disorder with heterogeneous symptom profiles and trajectories. Like many other neuropsychiatric disorders, clinical decision making related to diagnoses and choice of treatment is based on clinical assessments alone, and risk prediction for treatment success or resistance at an individual level remains sparse. An enormous effort to add biological markers to this risk prediction is ongoing. The role of lipids in normal brain functioning is well established, and several hypotheses about the role of lipids in the pathogenesis of neuropsychiatric disorders, including BD, have been made. The frequent comorbidity between neuropsychiatric disorders and cardiovascular disease, the genetic overlap of risk genes for severe mental disorders and genes involved in lipid regulation, and the lipid-altering effects of antipsychotics and mood stabilizers indicate that lipids could hold promise as biomarkers for neuropsychiatric disorders, including BD. To date, reviews of lipid biomarkers in schizophrenia and major depression have noted caveats for future investigations, while reviews of lipid biomarker research in BD is missing. In the current scoping review, we present a comprehensive overview of trends in previous research on lipid biomarkers in BD. The current literature varies greatly in the phenotypes investigated and study designs, leading to divergent findings. Small sample size; potential confounders related to physical activity, nutritional status, and medication use; and cross-sectional designs were frequently reported limitations. Future research may benefit from pivoting toward utilization of newer laboratory techniques such as lipidomics, but consistent use of study methods across cohorts is also needed.

Lowered PON1 activities are strongly associated with depression and bipolar disorder, recurrence of (hypo)mania and depression, increased disability and lowered quality of life

Objectives: Mood disorders (MDs) frequently co-exist with cardiovascular disease (CVD) and immune-inflammatory and oxidative stress are important shared pathophysiological pathways. Even though there has been an extensive investigation of the enzyme paraoxonase 1 (PON1) as a biomarker of susceptibility for CVD, there are few reports studying PON1 in MDs. The aim of this study was to determine the association between PON1 activities as well as functional genotypes and MD diagnosis, clinical characteristics and outcomes. Methods: PON1 activities and functional genotypes were assayed in 58 bipolar disorder (BD) and 32 major depressed patients (MDD) and compared with 59 controls. Results: Our findings show significantly lower PON1 total and CMPAase activities in MDs, which are partly related to the number of previous depressive and manic episodes. Lowered CMPAase activity is associated with a worse outcome of MDs as indicated by lowered quality of life (WHOQoL-BREF scale) and increased disability in the Sheeham scale. Conclusions: We hypothesise that lowered PON1 total and CMPAase activities may play a role in the pathophysiology of MDs by lowering antioxidant defences thereby increasing the risk of lipid peroxidation and inflammation; lowered inhibition of quorum-sensing lactones thereby increasing bacterial proliferation; and attenuated homocysteine thiolactone catabolism which may trigger immune-inflammatory response and/or induce neurotoxicity.

Why Should Psychiatrists and Neuroscientists Worry about Paraoxonase 1?

BACKGROUND

Nitro-oxidative stress (NOS) has been implicated in the pathophysiology of psychiatric disorders. The activity of the polymorphic antioxidant enzyme paraoxonase 1 (PON1) is altered in diseases where NOS is involved. PON1 activity may be estimated using different substrates some of which are influenced by PON1 polymorphisms.

OBJECTIVES

1) to review the association between PON1 activities and psychiatric diseases using a standardized PON1 substrate terminology in order to offer a state-of-the-art review; and 2) to review the efficacy of different strategies (nutrition, drugs, lifestyle) to enhance PON1 activities.

METHODS

The PubMed database was searched using the terms paraoxonase 1 and psychiatric diseases. Moreover, the database was also searched for clinical trials investigating strategies to enhance PON1 activity.

RESULTS

The studies support decreased PON1 activity as determined using phenylacetate (i.e., arylesterase or AREase) as a substrate, in depression, bipolar disorder, generalized anxiety disorder (GAD) and schizophrenia, especially in antipsychotic-free patients. PON1 activity as determined with paraoxon (i.e., POase activity) yields more controversial results, which can be explained by the lack of adjustment for the Q192R polymorphism. The few clinical trials investigating the influence of nutritional, lifestyle and drugs on PON1 activities in the general population suggest that some polyphenols, oleic acid, Mediterranean diet, no smoking, being physically active and statins may be effective strategies that increase PON1 activity.

CONCLUSION

Lowered PON1 activities appear to be a key component in the ongoing NOS processes that accompany affective disorders, GAD and schizophrenia. Treatments increasing attenuated PON1 activity could possibly be new drug targets for treating these disorders.

Anti-atherogenic properties of high-density lipoproteins in psychiatric patients before and after two months of atypical anti-psychotic therapy

Some of the medications used for the management of schizophrenia are associated with clinically significant increases in weight and adverse alterations in serum lipid levels. The aim of the study was to investigate the effect of short-term (two months) treatment with atypical anti-psychotics on coronary heart disease risk factors, including the functional properties of high-density lipoprotein (HDL), in psychiatric patients. Nineteen patients diagnosed with schizophrenia, schizoaffective, and bipolar disorder and ten healthy volunteers were enrolled in the study. In the present study blood was drawn at baseline and after two months of atypical anti-psychotic treatment. Wilcoxon non-parametric-test was used to examine differences in the psychotic group before and two months after treatment.Waist circumference and oxidative stress in psychiatric patients were higher compared with the control group. Serum-mediated cholesterol efflux capacity was lower in psychotic patients compared to controls. Two months of anti-psychotic therapy was associated with increased abdominal obesity, decreased paraoxonase lactonase activity, but with no further change in serum-mediated cholesterol efflux from macrophages. Psychotic patients have low serum-mediated cholesterol efflux from macrophages as a parameter of HDL functionality. Atypical anti-psychotic treatment for two months increased metabolic derangements in these patients but without further decrement in serum-mediated cholesterol efflux.

Bipolar disorders in the Arab world: a critical review

Bipolar disorders are common psychiatric disorders that affect 1-5% of the population worldwide. Major advances in the epidemiology, pathophysiology, and treatment of the disorders have recently occurred. The majority of published reports, however, originate from the Western hemisphere, mostly Europe and the United States. There is a shortage of data from the Arab world on bipolar disorders. In an era of globalization and rapid communication, it is not clear to what extent research findings pertaining to one part of the world are by necessity applicable to other parts. Psychiatric disorders are known to be affected by the culture in which they occur, and knowledge of variations in illness presentation in different ethnic groups is also increasing. However, knowledge of variations affecting Arab populations remains quite limited. This paper provides a critical review of the literature on bipolar affective disorders in the Arab world, pointing to major gaps in knowledge and future opportunities to fill these gaps.

Paraoxonase 1 activity and lipid profile in schizophrenic patients

OBJECTIVE

This study aimed to investigate the variations of paraoxonase 1 (PON1) activity and lipid profile in patients with schizophrenia and the association of this activity with the sociodemographic, clinical and therapeutical characteristics of this population.

PATIENTS AND METHODS

Our cross-sectional study included 140 schizophrenic patients and 119 control subjects aged respectively 37.3±10.4 and 41.4±10 years. PON1 activity was determined using Konelab 30™ equipment (Thermo Electron Corporation). Plasma total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (c-HDL) and low-density lipoprotein cholesterol (c-LDL) concentrations were determined using Cobas 6000™ (Roche Diagnostics), apolipoproteins (ApoA1, ApoB) and lipoprotein (a) (Lp(a)) were determined using Integra 400 plus (Roche Diagnostics).

RESULTS

Compared to controls, patients had no significant decrease of PON1 activity and significantly lower ApoA1, c-HDL levels, and significantly higher levels of TG, ApoB, Lp(a) and TC/c-HDL and ApoB/ApoA1 ratios. Furthermore, PON1 activity was correlated with TG/c-HDL ratio. The lowest PON1 activity was noted in obese patients, in paranoid sub-type and in patients treated with combination of typical and atypical antipsychotics without significant difference. Moreover, it was associated with gender and cigarette smoking but not with alcohol consumption status.

CONCLUSION

Schizophrenic patients had a decrease in PON1 activity and perturbations in their lipid profiles that contribute to increase the risk of cardiovascular diseases. In addition, our results revealed that there was no association between the decrease of PON1 activity and any demographic or clinical characteristics. Therefore, such patients require specific care, particularly with regard to their lipid profile.

Lowered plasma paraoxonase (PON)1 activity is a trait marker of major depression and PON1 Q192R gene polymorphism-smoking interactions differentially predict the odds of major depression and bipolar disorder

BACKGROUND

Major depression and bipolar disorder are accompanied by the activation of immune-inflammatory and Oxidative and Nitrosative Stress (O&NS) pathways and lowered levels of antioxidants. Paraoxonase (PON)1 (EC 3.1.8.1) is an antioxidant bound to High Density Lipoprotein (HDL). Polymorphisms in the PON1 Q192R coding sequence determine three functional genotypes, i.e. 192QQ, 192QR and 192RR.

AIMS

This study was carried out to delineate the associations of plasma PON1 activity and functional PON1 Q192R genotypes in major depression and bipolar disorder.

METHODS

PON1 status that is plasma PON1 abundance and three functional PON1 Q192R genotypes were assayed in 91 major depressed and 45 bipolar patients and compared to 199 normal controls.

RESULTS

Major depression, but not bipolar disorder, was accompanied by lowered PON1 activity. PON1 activity was decreased by smoking and a diagnosis by genotype interaction (i.e. lower PON1 in major depression with the QQ genotype). Logistic regression showed that smoking by QQ genotype significantly increased the odds of bipolar disorder and that major depression was predicted by plasma PON1 activity, serum HDL cholesterol and interactions between genotype×smoking.

DISCUSSION

The results suggest that lowered plasma PON1 activity is a trait marker of major depression and that PONQ192R gene-environment (smoking) interactions differentially predict the odds of depression and bipolar disorder.

LIMITATIONS

Association studies are prone to a risk of false positive findings and replication is essential.

CONCLUSIONS

The findings suggest that there are differential PON1 Q192R functional genotype×environment interactions in major depression and bipolar disorder. The effects of lowered PON1 activity may contribute to increased O&NS and immune-inflammatory burden in depression. PON1 status may contribute to the comorbidity between depression and other immune- and O&NS-related disorders, e.g. cardiovascular disorder.

Can paraoxonase 1 polymorphisms (L55 M and Q192 R) protect children with type 1 diabetes against lipid abnormalities?

BACKGROUND

Only a few studies have focused on the possible modulatory role of paraoxonase 1 (PON1) polymorphisms in lipid profiles, especially in children and in adolescents with type 1 diabetes (T1D).

OBJECTIVE

We propose to study the association between PON1 polymorphisms (PON1-55 and PON1-192) and a lipid profile in a young Tunisian population with T1D.

METHODS

The study compared 122 children and adolescents with T1D with 97 controls. Genomic DNA was collected from 116 patients and 91 controls. Lipid parameters were determined by automated methods. PON1 activity was measured by a spectrophotometric method and genotyping of the PON1 gene was assessed by multiplex polymerase chain reaction followed by restriction fragment-length polymorphism.

RESULTS

A significant increase in total cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol (LDL-C), apolipoprotein B (ApoB), and lipoprotein (a) (Lp(a)) and a significant decrease in apolipoprotein A1 (ApoA1), ApoA1/ApoB ratio, and PON1 activity/HDL-C ratio were observed in children with T1D compared with controls. In the LLQR haplotype, the group with diabetes showed significantly higher values of total cholesterol, LDL-C, apoB, Lp(a), and apoA1/apoB ratio compared with the control group. Those with diabetes with the LLQQ haplotype showed a significant decrease in LDL-C and Lp(a) compared with controls (P < .0001).

CONCLUSION

PON1 polymorphisms (PON1-55 and PON1-192) seem to be involved in the altering the lipid profile in T1D. The LLQR haplotype provided an atherogenic lipid profile in children with T1D compared with controls. LLQQ haplotype seemed to have a protective effect against the increase in LDL-C and Lp(a) that are heavily involved in the development of cardiovascular diseases.

Association between bipolar I disorder and the L55M and Q192R polymorphisms of the paraoxonase 1 (PON1) gene

BACKGROUND

The purpose of this work was to study the association between the PON1 L55M and Q192R polymorphisms and bipolar I disorder in Tunisian patients and to explore their relation to the sociodemographic, clinical and therapeutic characteristics of this disease.

PATIENTS AND METHODS

Our study included 109 patients with bipolar I disorder and 110 controls aged 39.4±11.8 and 37.3±9.2 years, respectively. L55M and Q192R of the PON1 gene polymorphisms were determined by multiplex polymerase chain reaction.

RESULTS

Significant difference was detected in the distribution of the genotype frequencies of L55M and Q192R polymorphisms (χ²=6.32, df=2, p=0.04; χ²=10.15, df=2, p=0.006 respectively) between patients and controls. We noted significant association between bipolar I disorder and QR and RR genotypes (OR 2.06, CI 95% 1.10-3.84, p=0.02; OR 1.72, CI 95% 1.07-2.75, p=0.02 respectively) and between this disease and LM and MM genotypes (OR 2.22, CI 95% 1.19-4.15, p=0.012; OR 3.04, CI 95% 1.60-5.77, p=0.01 respectively). There were no significant differences in gender, age at onset, illness episode and treatment among all genotypes. However, Q192R polymorphism was significantly associated with age and patients with RR genotype were the youngest.

CONCLUSION

Bipolar I disorder was significantly associated with L55M and Q192R polymorphisms, suggesting that these polymorphisms may play a role for development of bipolar I disorder. There was no significant association between the clinical and therapeutic characteristics of this population and these polymorphisms. Further studies are required to clarify the implication of these polymorphisms in the pathophysiology of bipolar I disorder.

Thyroid function and lipid profile in bipolar I patients

OBJECTIVE

This study aims to evaluate the prevalence of thyroid dysfunctions and to explore their association with perturbations in lipid profile in bipolar I patients.

PATIENTS AND METHODS

Our study included 130 bipolar I patients diagnosed according to the DSM IV, and 124 control subjects aged respectively 37.9±12.1 and 37.6±13.2 years. TSH and FT4 were determined using electrochemiluminescence. Total cholesterol, triglycerides, c-LDL and c-HDL were determined by enzymatic colorimetric methods and ApoA1, ApoB and Lp(a) by immunoturbidimetric techniques on Konélab 30™.

RESULTS

Patients had significantly higher TSH values than controls and had perturbations in lipid profile. 0.7% and 28.5% of patients had respectively hyperthyroidism and hypothyroidism. Hypothyroidism was associated with obesity and perturbations in lipid profile particularly increase in total cholesterol, c-LDL, ApoB, ApoB/ApoA1 and Lp(a) and decrease in ApoA1 and c-HDL. Moreover, it was associated with lithium and valproic acid treatment.

CONCLUSIONS

Hypothyroidism was frequent in bipolar patients. It was significantly associated with obesity and perturbations in lipid profile. Therefore, bipolar patients require specific care, particularly for thyroid, lipid profile and weight; the effectiveness of this care will be evaluated during follow-up period.