Heavy metal concentrations and clinical symptoms in patients diagnosed with schizophrenia related to cigarette smoking

In our study, blood concentrations of lead (Pb), arsenic (As), and cadmium (Cd) and urine concentrations of thallium (Tl) were measured together with related symptoms of heavy metal poisoning in cigarette smoking volunteers diagnosed with schizophrenia, in cigarette smokers not diagnosed with schizophrenia, and in the control group of non-smokers and not diagnosed with schizophrenia volunteers. Our study was performed on 171 volunteers divided into the following subgroups: patients diagnosed with schizophrenia with at least 1 year of continuous cigarette smoking experience (56 participants), cigarette smokers not diagnosed with schizophrenia with at least one year of continuous smoking experience (58), and control group (not diagnosed with schizophrenia and non-smoking volunteers) (57). Smoking durations of cigarette smokers diagnosed with schizophrenia and cigarette smokers not diagnosed with schizophrenia are not similar (p = 0.431). Blood Pb, As, and Cd concentrations and urine Tl concentrations were the highest in the subgroup of cigarette smokers not diagnosed with schizophrenia, followed by the subgroup of cigarette smokers diagnosed with schizophrenia, and the control group. Only blood Pb concentrations were significantly higher (probability value p < 0.05) in the group of cigarette smokers not diagnosed with schizophrenia (5.16 μg/dL), comparing to the group of cigarette smokers diagnosed with schizophrenia (3.83 μg/dL) and to the control group (3.43 μg/dL). Blood Cd and As concentrations and urine Tl concentrations were significantly higher (p < 0.05) in cigarette smokers not diagnosed with schizophrenia than in the control group. The results revealed a statistically significant positive correlation (p < 0.001) in the cigarette smokers in the schizophrenia diagnosed group between blood Pb, blood As, and urine Tl concentrations and the duration of cigarette smoking.

Reprint of: Elemental dysregulation in psychotic spectrum disorders: A review and research synthesis

Accumulating evidence from observational studies, genetic research, and animal models suggests a relationship between toxic and nutritive elements and psychotic spectrum disorders (PSD). This review systematically evaluates the current research evidence for two hypotheses: 1) that exposures to abnormal levels of toxic and nutritive elements early in life contributes to the subsequent development of PSD, and 2) that an imbalance of element levels is linked to psychotic illness and clinical severity. We focused on the extant literature on five elements, lead (Pb), copper (Cu), magnesium (Mg), manganese (Mn), and zinc (Zn), because of their previously documented associations with psychiatric problems and the availability of pertinent literature. The review identified 38 studies of which 11 measured Pb, 27 measured Cu, 16 measured Mg, 15 measured Mn, and 25 measured Zn concentrations in PSD patients and controls. A majority of research has been conducted on nutritive element imbalance, and findings are largely mixed. While it is biologically plausible that element dysregulation is an important modifiable risk factor for PSD, more research into exposure in early life is needed to better characterize this relationship.

Elemental dysregulation in psychotic spectrum disorders: A review and research synthesis

Accumulating evidence from observational studies, genetic research, and animal models suggests a relationship between toxic and nutritive elements and psychotic spectrum disorders (PSD). This review systematically evaluates the current research evidence for two hypotheses: 1) that exposures to abnormal levels of toxic and nutritive elements early in life contributes to the subsequent development of PSD, and 2) that an imbalance of element levels is linked to psychotic illness and clinical severity. We focused on the extant literature on five elements, lead (Pb), copper (Cu), magnesium (Mg), manganese (Mn), and zinc (Zn), because of their previously documented associations with psychiatric problems and the availability of pertinent literature. The review identified 38 studies of which 11 measured Pb, 27 measured Cu, 16 measured Mg, 15 measured Mn, and 25 measured Zn concentrations in PSD patients and controls. A majority of research has been conducted on nutritive element imbalance, and findings are largely mixed. While it is biologically plausible that element dysregulation is an important modifiable risk factor for PSD, more research into exposure in early life is needed to better characterize this relationship.

Unravelling neurological disorders through metallomics-based approaches

Understanding the biological process involving metals and biomolecules in the brain is essential for establishing the origin of neurological disorders, such as neurodegenerative and psychiatric diseases. From this perspective, this critical review presents recent advances in this topic, showing possible mechanisms involving the disruption of metal homeostasis and the pathogenesis of neurological disorders. We also discuss the main challenges observed in metallomics studies associated with neurological disorders, including those related to sample preparation and analyte quantification.

A Novel Variant in Dopamine Receptor Type 2 Gene is Associated with Schizophrenia

BACKGROUND

Being the primary target of antipsychotic therapy, dopamine receptor type 2 (DRD2) remains a point of interest in schizophrenia pathology. Polymorphisms in DRD2 have been shown to alter patients' response to antipsychotics. DRD2 SNP rs6275 (C>T) have found to be associated with schizophrenia in different populations; however, data remains inconsistent.

AIM OF THE STUDY

Keeping in view the genetic diversity the present study was aimed to explore association of rs6275 with schizophrenia in population from Pakistan.

METHOD

Using Diagnostic and statistical Manual 5 (DSM 5) criteria, 100 schizophrenia cases and 100 controls (individuals without any psychiatric illness) were enrolled in the study. Severity of illness was determined using PANSS score. Genotyping was done via Sanger sequencing. MEGA-X was used to align the sequences, Expasy translate tool was used to translate nucleotide sequences. Difference in genotype and allele frequencies between cases and controls was determined using χ² test.

RESULT

No significant difference in genotype or allele frequencies of rs6275 (p >0.0.5) was found between cases and controls. Interestingly, a novel SNP (C>A, Pro297Thr) was spotted during electropherogram analysis at position chr11:113412805. Significant difference was found in genotype and allele frequency of this novel SNP among schizophrenia cases and controls (p = 0.003).

CONCLUSION

No association of rs6275 was observed with schizophrenia in Pakistani population. However, the study found significant association of a novel missense SNP of DRD2 at chr11:113412805 (C>T) with schizophrenia in Pakistani population. A large-scale multicenter study will be required to confirm the association of this novel SNP with schizophrenia.

Overview of schizophrenia research and treatment in Pakistan

Mental health is the most neglected health sector in Pakistan, and the majority of citizens have limited or no access to primary and secondary psychiatric services. The incidence of schizophrenia (SCZ) has increased at an alarming rate in Pakistan, relative to that of other psychiatric disorders. While numerous studies have investigated SCZ, few have addressed the issue about the Pakistani population. In the present review, the researchers discuss current data integral to the prevalence, pathophysiology, and molecular genetics of SCZ; treatment approaches to the disease; and patient responses to drugs prescribed for SCZ in Pakistan. Most Pakistani patients exhibit poor responses to antipsychotic drugs. Based on our review, the researchers hypothesize that genetic dissimilarities between Pakistani and Western populations contribute to such poor responses. Consequently, an understanding of such genetic differences and the provision of personalized treatment may simultaneously aid in improving SCZ treatment in Pakistan.

Synonymous polymorphism rs201256011 in dopamine receptor type 2 gene is associated with schizophrenia and PANSS score in Pakistani population: A first report

AIM

Variations of dopamine receptor type 2 (DRD2) are among the key factors involved in the pathology of schizophrenia. Presence of certain SNPs in DRD2 gene also amend patients' response to antipsychotics. Keeping in view the genetic diversity among populations and important role of DRD2 polymorphisms in schizophrenia, we aimed to study two of its SNPs rs1801028 and rs6277 in patients with schizophrenia from Pakistan.

METHODS

A total of 100 schizophrenia cases and 100 healthy controls were recruited. DNA was extracted from whole blood followed by PCR, Sanger sequencing and genotyping of two SNPs, that is, rs1801028 and rs6277.

RESULTS

No association of rs1801028 and rs6277 was found with schizophrenia in Pakistani population (P > .05). Highlight of our study is the association of polymorphism rs201256011 with schizophrenia (P = .001), which is being reported for the first time. Significant association of rs201256011 was also found with Positive and Negative Syndrome Scale negative, cognitive and total score (P < .05).

CONCLUSION

In conclusion, genetic variants rs1801028 and rs6277 of DRD2 are not associated with schizophrenia in Pakistani population. While, previously unreported polymorphism rs201256011 have shown significant association with schizophrenia and its severity. A large scale multicentre replication study is required to confirm the association of this SNP with schizophrenia.

Is there any association between manganese level and schizophrenia? - a descriptive review

Introduction: Manganese has a role in the membrane transport systems, synthesis of protein, vitamin C, and vitamins B, catalysis of hematopoiesis, regulation of the endocrine, immune system, blood sugar, reproduction, digestion, and blood coagulation. Furthermore, the level of manganese concentrations in human body appears to affect the occurrence of schizophrenia. The aim of this study was to search for relationships between the manganese level and the onset of schizophrenia.

Material and methods: A descriptive review was performed based on a literature search on Medline and Google scholar from 2003 to 2020, using keywords: schizophrenia, manganese, Mn. The included studies were meta-analyses, case-control studies, and cohort studies that examined differences in manganese concentrations in patients with schizophrenia and healthy controls.

Result: Eight studies were selected for the review, with one reporting elevated levels of manganese, two showing no significant differences, and the rest including two meta-analyses stating lower manganese concentrations in patients with schizophrenia in comparison with controls.

Conclusion: In most of the researched studies, manganese concentrations in patients with schizophrenia were lower than in control groups, but not all of them reached the same conclusions. The relationship between manganese levels and schizophrenia must be further investigated.

Trace elements in schizophrenia: a systematic review and meta-analysis of 39 studies (N = 5151 participants)

Context

The pathogenesis of schizophrenia appears to be multifaceted.

Objective

The aim of this meta-analysis of studies that investigated blood and hair concentrations of trace elements in people diagnosed with schizophrenia was to determine whether levels of trace elements in patients with schizophrenia differ from those in healthy individuals.

Data Sources

The PubMed, Scopus, and Web of Science databases were searched to January 2018.

Study Selection

Studies that compared concentrations of trace elements in patients with schizophrenia with those in healthy controls, in patients with schizophrenia under different treatment regimens, or in patients with schizophrenia at different stages of disease were included.

Data Extraction

Data on study and sample characteristics and measures of trace elements were extracted.

Results

Thirty-nine studies with a total of 5151 participants were included. Meta-analysis of combined plasma and serum data showed higher levels of copper, lower levels of iron, and lower levels of zinc among patients with schizophrenia vs controls without schizophrenia. Subgroup analyses confirmed the following: higher levels of copper in plasma, in users of typical antipsychotic drugs, and in males; lower levels of zinc in serum, in patients in Asia, in drug-naive/drug-free patients, and in inpatients; lower levels of iron in serum, in patients in Asia, in drug-naive/drug-free patients, in patients on antipsychotic drugs, in inpatients, in patients with acute or newly diagnosed schizophrenia, in patients with chronic or previously diagnosed schizophrenia, and in males; and lower levels of manganese in plasma and in patients with chronic or previously diagnosed schizophrenia.

Conclusions

This meta-analysis provides evidence of an excess of copper, along with deficiencies of zinc, iron, and manganese, in patients with schizophrenia.

Nutritional Deficiencies and Clinical Correlates in First-Episode Psychosis: A Systematic Review and Meta-analysis

Objective

Diet is increasingly recognized as a potentially modifiable factor influencing the onset and outcomes of psychiatric disorders. Whereas, previous research has shown long-term schizophrenia is associated with various nutritional deficiencies, this meta-analysis aimed to determine the prevalence and extent of nutritional deficits in first-episode psychosis (FEP).

Method

A search of electronic databases conducted in July 2017 identified 28 eligible studies, examining blood levels of 6 vitamins and 10 minerals across 2612 individuals: 1221 individuals with FEP and 1391 control subjects. Meta-analyses compared nutrient levels in FEP to nonpsychiatric controls. Clinical correlates of nutritional status in patient samples were systematically reviewed.

Results

Significantly lower blood levels of folate (N = 6, n = 827, g = -0.624, 95% confidence interval [CI] = -1.176 to -0.072, P = .027) and vitamin D (N = 7, n = 906, g = -1.055, 95% CI = -1.99 to -0.119, P = .027) were found in FEP compared to healthy controls. Synthesis of clinical correlates found both folate and vitamin D held significant inverse relationships with psychiatric symptoms in FEP. There was also limited evidence for serum level reductions of vitamin C (N = 2, n = 96, g = -2.207, 95% CI = -3.71 to -0.71, P = .004). No differences were found for other vitamins or minerals.

Conclusions

Deficits in vitamin D and folate previously observed in long-term schizophrenia appear to exist from illness onset, and are associated with worse symptomology. Further research must examine the direction and nature of these relationships (ie, mediator, moderator, or marker) with clinical status in FEP. Future trials assessing efficacy of nutrient supplementation in FEP samples should consider targeting and stratifying for baseline deficiency.

Metallomics Applied to the Study of Neurodegenerative and Mental Diseases

Biochemical imbalances, provoked by aging or a secondary illness, might directly affect the brain, causing severe problems, such as loss of memory or alteration of behavior patterns. Brain disorders are usually classified as injuries (such as stroke, hematomas, and concussions), tumors, and neurodegenerative (such as Parkinson's and Alzheimer's diseases) and mental (such as depression, bipolar disorder, schizophrenia) diseases. As the pathophysiology of these illnesses is not completely established and multiple factors are involved, metallomics, a bioanalytical strategy that allows the detection of metal ions and metalloproteins in diverse biological matrices, is of extreme relevance in identifying which elements are affected by a disease and/or treatment. Thus, determining which element ions suffer disturbances in their homeostasis during the disease progress is relevant to understand the biochemical changes and propose new drug targets. In addition, it is well known that oxidative stress plays an important role in the development of pathological neurodegenerative and mental diseases, which may be caused by metal ion dyshomeostasis, so it is also important to understand endogenous antioxidant metalloprotein and metalloenzyme mechanisms in this regard. In this context, recent applications of metallomics in the study of neurodegenerative and mental disorders are discussed in this chapter, as well as future trends in this research area.

Data on copper level in the blood of patients with normal and abnormal angiography

In this data article, we measured the levels of copper in the blood of patients undergoing coronary angiography. The samples were taken from patients with cardiovascular disease in Bushehr׳s university hospital, Iran. Patients were divided in two groups: normal angiography and abnormal angiography. After the chemical digestion of samples, the concentration levels of Cu in both groups were determined by using inductively coupled plasma optical spectrometry (ICP-OES).