Leukocyte telomere length variation in different stages of schizophrenia

Relation of ATPase6 Mutations and Telomere Length in Schizophrenia Patients

Objective

Schizophrenia is a serious mental disorder. Mutations in mitochondrial genes can change energy metabolism. Telomere is a tandem sequence at the end of chromosomes. Shorter telomere length has been shown in schizophrenia. The aim of this study was to determine the relationship between ATPase6 gene mutations and telomere length in schizophrenia patients.

Methods

Blood samples of 34 patients and 34 healthy controls were used. In this study conventional PCR, Sanger sequencing technic and real-time PCR were utilized.

Results

Five different mutations (A8860G, A8836, G8697A, C8676T, and A8701G) in the ATPase6 gene were identified in schizophrenia patients. The most seen mutation was A8860G (94%). Telomere length analysis indicated the relation of ATPase6 gene mutations and telomere length variations (p = 0.001). Patients carrying the A8860G mutation had shorter telomere lengths than patients carrying other mutations. Comparing telomere length between schizophrenia patients and healthy controls revealed that the mean telomere length of schizophrenia patients was shorter than healthy controls (p = 0.006). The demographic analysis demonstrated a significant relationship between marital status and telomere length (p = 0.011). Besides that, the duration of the illness is another factor that impacts telomere length (p = 0.044). There is no significant relation between telomere length and other clinical and demographic characteristics including education status, age, gender, etc.

Conclusion

In conclusion, telomere length and ATPase6 gene mutations have a significant relation. Studies with larger patient populations and investigation of other mitochondrial gene mutations will make the clearer link between telomere length and mitochondrial mutations.

Leukocyte telomere length is not shortened in methamphetamine dependence or methamphetamine-induced psychosis but is increased following traumatic events

OBJECTIVE

This study aims to examine the effects of methamphetamine (MA) use and dependence and MA withdrawal symptoms on the telomere length and whether shortening of the latter is associated with MA-induced psychosis (MIP).

METHODS

This study included 185 MA-abuse, 118 MA-dependent, and 67 MIP patients, diagnosed using DSM-IV criteria. The Semi-structured Assessment for Drug Dependence and Alcoholism (SSADDA) questionnaire was employed to collect MA-related data. MIP was confirmed using the Methamphetamine Experience Questionnaire (MEQ). The leukocyte telomere length was measured using real-time polymerase chain reaction measuring the Telomere/Single gene ratio (T/S ratio). Data were analysed using multivariate statistical analyses.

RESULTS

There were no significant associations between the T/S ratio and severity of MA-use, MIP, and MA withdrawal symptoms. MIP was significantly predicted by alcohol dependence, antisocial personality disorder, and MA-use severity. There were significantly positive associations between the T/S ratio and previous traumatic and life-threatening events. The T/S ratio was not affected by alcohol and nicotine dependence. Alcohol and nicotine dependence, antisocial personality disorder, and severity of MA use increased risk of MA withdrawal symptoms.

CONCLUSION

MIP and MA-use severity are not associated with leukocyte telomere length, but previous traumatic and life-threatening events are associated with increased telomere length.

Telomere is shortened in patients with irritable bowel syndrome in the Chinese population

BACKGROUND AND AIM

Telomere shortening is an accepted indicator of aging. Many studies have investigated an association between leukocyte telomere length (LTL) and psychiatric disorders. Mental or psychological factors could be an important cause of irritable bowel syndrome (IBS). However, there are currently few research evaluating correlations between LTL and IBS.

METHODS

We examined associations between LTL and IBS using quantitative polymerase chain reaction in independent cohorts, including 205 patients with IBS and 189 healthy controls. Furthermore, we examined whether mental or psychological factors, types of IBS, duration of IBS and antidepressants had an association with LTL in patients with IBS.

RESULTS

Among total samples, patients with IBS presented shorter LTL when compared to healthy controls (P < 0.0001). Moreover, in subgroup analyses of patients with IBS, not only the LTL in patients with IBS caused by mental or psychological factors was shorter (P < 0.0001), but also in patients with IBS that were caused by other factors (P = 0.0082). Furthermore, LTL in patients with IBS who had taken antidepressants for more than 1 month was longer than that in patients with IBS who did not take antidepressants or took for less than 1 month (P < 0.0001).

CONCLUSIONS

This is the first study to describe the relationship between LTL and IBS. This study showed significantly shorter telomeres in patients with IBS. Our findings suggest that LTL may hold the potential to serve as a predictor of IBS diagnosis.

Telomere Length as a Marker of Suicidal Risk in Schizophrenia

BACKGROUND: Schizophrenia and suicidal behavior are associated with shortening in the length of telomeres. The aim of the study was to compare the content (pg/mcg) of telomeric repeat in DNA isolated from peripheral blood cells in three groups of subjects: patients with schizophrenia and a history of suicide attempts, patients with schizophrenia without suicidal tendencies, and healthy control volunteers. METHODS: Relapses according to gender and age were examined in 47 patients with schizophrenia with suicidal behavior, 47 patients without self-destructive conditions, and 47 volunteers with healthy control and maintenance for the content of telomeric and the number of copies of mitochondrial DNA (mtDNA) in peripheral blood leukocytes. RESULTS: Analysis of determining the content of telomeric repeat (TR) in the DNA of massive weight gain in the series: patients with schizophrenia and suicidal attempts patients with schizophrenia without suicidal observations healthy controls (22528.4 (227 [190; 250]) vs. 24321 (245 [228; 260]) vs. 25517.9 (255 [242; 266]), p 0.005. The same trend is observed for the number of mtDNA copies (257101.5 (250 [194; 297])) vs. 262.359.3 (254 [217; 312]) vs. 27279.9 (274 [213; 304]); p=0.012), but no significant differences were recorded. CONCLUSIONS: For the first time, the phenomenon of telomere shortening was discovered in schizophrenics with suicidal risk. The length of the telomere corresponds to the parameter of a biological marker an objectively measured indicator of normal or pathological processes, but gaining an idea of its reliability is still necessary for verification with an assessment of its sensitivity, specificity, and positive and negative predictive value. The telomere may be considered a putative predictive indicator of suicidal risk.

Leukocyte telomere length in patients with schizophrenia and related disorders: a meta-analysis of case-control studies

CONTEXT

Telomere length may serve as a biomarker of cellular aging. The literature assessing telomere length in schizophrenia contains conflicting results.

OBJECTIVE

To assess differences in leukocyte telomere length (LTL) in peripheral blood in patients with schizophrenia and related disorders and healthy controls and to explore the effect of potential confounding variables.

DATA SOURCES

A search of Ovid MEDLINE, and Proquest databases was conducted to identify appropriate studies published from database inception through December 2020. The review protocol was registered with PROSPERO-ID: CRD42021233280.

STUDY SELECTION

The initial literature search yielded 192 studies. After study selection in 3 phases, we included 29 samples from 22 studies in the meta-analysis database.

DATA EXTRACTION

We used random effects and meta-regression models to derive Cohen d values with pooled 95% confidence intervals (CI) as estimates of effect size (ES) and to test effects of potential moderators.

RESULTS

The overall meta-analysis included 4145 patients with schizophrenia and related disorders and 4184 healthy controls and showed that LTL was significantly shorter in patients, with a small to medium effect size (ES, -0.388; 95% CI, -0.492 to -0.283; p < 0.001). Subgroup meta-analyses did not find a significant effect of age or illness duration on differences in LTL in patients with psychosis relative to controls. Meta-regression analyses showed that none of the putative moderators had a significant effect on effect size estimates.

CONCLUSIONS

This meta-analysis find further support for the hypothesis of accelerated cellular aging in schizophrenia and related disorders and highlights the need for large longitudinal studies with repeated LTL measurements over time and appropriate assessments of associated factors.

Correlation between telomere length and efficacy of oral and long-acting injectable antipsychotics on severity and cognitive impairment of schizophrenia

OBJECTIVE

To study the correlation between telomere length (TL) and long-acting injectable (LAI) and oral atypical antipsychotic (OAA) efficacy on schizophrenia (SCZ) severity and cognitive impairment.

METHODS

Sixty Schizophrenia patients of 18-50 years and of either sex were included in a 12-week study. Thirty patients were recruited in each group, LAI and OAA. Positive and Negative Syndrome Scale (PANSS) and National Institute of Mental Health and Neuro-Sciences (NIMHANS) neuropsychological battery tests were evaluated at baseline and 12 weeks. TL was estimated at baseline.

RESULTS

Both groups showed a significant improvement in PANSS and NIMHANS battery test scores after treatment (p < 0.001) within the group, though not between the groups. Mean TL at baseline was 407.58 ± 143.93 and 443.40 ± 178.46 in LAI and OAA groups respectively. A significant negative correlation (r = -0.28, p = 0.03) of TL was seen with the mean change in negative PANSS score after treatment.

CONCLUSIONS

LAI antipsychotics are similar to OAA in decreasing the disorder severity and improving the cognitive impairment in schizophrenia. Also, patients who have shorter TL show greater improvement in the negative PANSS score. Hence, TL holds the potential of predicting antipsychotic drug response in schizophrenia patients.KEY POINTSLong-acting injectable antipsychotic was comparable to oral atypical antipsychotics in bringing out improvement in disorder severity, cognitive functions over 12 weeks.Shorter telomere length has been found to be associated with a greater response in negative symptoms of schizophrenia.

Sex-specific involvement of the Notch-JAG pathway in social recognition

Under the hypothesis that olfactory neural epithelium gene expression profiles may be useful to look for disease-relevant neuronal signatures, we examined microarray gene expression in olfactory neuronal cells and underscored Notch-JAG pathway molecules in association with schizophrenia (SZ). The microarray profiling study underscored JAG1 as the most promising candidate. Combined with further validation with real-time PCR, downregulation of NOTCH1 was statistically significant. Accordingly, we reverse-translated the significant finding from a surrogate tissue for neurons, and studied the behavioral profile of Notch1^+/- mice. We found a specific impairment in social novelty recognition, whereas other behaviors, such as sociability, novel object recognition and olfaction of social odors, were normal. This social novelty recognition deficit was male-specific and was rescued by rapamycin treatment. Based on the results from the animal model, we next tested whether patients with psychosis might have male-specific alterations in social cognition in association with the expression of NOTCH1 or JAG1. In our first episode psychosis cohort, we observed a specific correlation between the expression of JAG1 and a face processing measure only in male patients. The expression of JAG1 was not correlated with any other cognitive and symptomatic scales in all subjects. Together, although we acknowledge the pioneering and exploratory nature, the present work that combines both human and animal studies in a reciprocal manner suggests a novel role for the Notch-JAG pathway in a behavioral dimension(s) related to social cognition in psychotic disorders in a male-specific manner.

Correlation between telomere length and biomarkers of oxidative stress in human aging

The telomere length (TL) has increasingly been used as a biomarker of human aging because it has been shown to predict the chances of survival and longevity. Oxidative stress is presumed to be a major cause of telomere shortening but the importance of oxidative stress as a determinant of telomere shortening remains less clear and has recently been questioned. We analyzed 105 healthy subjects of both sexes between the ages of 20-77 years. The TL, and, biomarkers of oxidative stress were estimated as per standard protocols. A significant (p<0.001) age-dependent decline in TL was observed. TL was positively correlated with the ferric reducing ability of plasma (FRAP value) (r=0.8811) and reduced glutathione (GSH) (r=0.8209) while negatively correlated with malondialdehyde (MDA) (r=-0.7191). Our findings supported the idea of a possible correlation between the TL and biomarkers of oxidative stress in aging. The study has remarkable scope in medical science as the findings on correlation of TL with biomarkers of oxidative stress in aging are novel and they will help in further research against oxidative stress.

Aging biological markers in a cohort of antipsychotic-naïve first-episode psychosis patients

Schizophrenia is a severe and multifactorial disorder with an unknown causative pathophysiology. Abnormalities in neurodevelopmental and aging processes have been reported. Relative telomere length (RTL) and DNA methylation age (DMA), well-known biomarkers for estimating biological age, are both commonly altered in patients with schizophrenia compared to healthy controls. However, few studies investigated these aging biomarkers in first-episode psychosis (FEP) and in antipsychotic-naïve patients. To cover the existing gap regarding DMA and RTL in FEP and antipsychotic treatment, we aimed to verify whether those aging markers could be associated with psychosis and treatment response. Thus, we evaluated these measures in the blood of FEP antipsychotic-naïve patients and healthy controls (HC), as well as the response to antipsychotics after 10 weeks of treatment with risperidone. RTL was measured in 392 subjects, being 80 FEP and 312 HC using qPCR, while DMA was analyzed in a subset of 60 HC, 60 FEP patients (antipsychotic-naïve) and 59 FEP-10W (after treatment) using the "Multi-tissue Predictor"and the Infinium HumanMethylation450 BeadChip Kit. We observed diminished DMA and longer RTL in FEP patients before treatment compared to healthy controls, indicating a decelerated aging process in those patients. We found no statistical difference between responder and non-responder patients at baseline for both markers. An increased DMA was observed in patients after 10 weeks of treatment, however, after adjusting for blood cell composition, no significant association remained. Our findings indicate a decelerated aging process in the early phases of the disease.

No alteration of leukocyte telomere length in first episode psychosis

Both shorter telomeres and schizophrenia have been associated with a decrease in life expectancy. Furthermore, several studies found a shorter telomere length (TL) in schizophrenia. Understanding whether or not telomere shortening is directly related to pathophysiology of schizophrenia or is a consequence of a cumulative exposure to chronic stress is of major importance. Comparing the TL of subjects at the very beginning of the disease (FEP) and control subjects could help to decide between these two hypotheses. The aim of the present study was to compare TL between FEP subjects (N=91) and controls (N=137). After accounting for multiple potential confounders, no significant association was observed between FEP and TL. Our result is consistent with the hypothesis that psycho-social stress / adversities and stressful situations in people with schizophrenia affect TL rather than that telomere erosion contributes to the development of this disorder.

Telomere Length and ADHD Symptoms in Young Adults

Objective: Previous research examining telomeres in individuals with neuropsychiatric disorders shows that greater illness, symptoms, or cognitive impairment are linked with shorter telomeres. However, the relationships of telomere length and neuropsychological processes or psychiatric symptoms are not understood in individuals with Attention Deficit/Hyperactivity Disorder (ADHD). Method: 390 young adults with and without ADHD completed a multi-informant diagnostic assessment and neuropsychological testing battery. Participant DNA was isolated from saliva samples, and telomere length was determined using qPCR. Results: Linear regression models demonstrated the only significant association to survive correction for multiple testing was for childhood hyperactivity-impulsivity symptoms and longer telomere length. Conclusion: Contrary to expectations, longer telomere length in young adults was associated only with childhood ADHD symptoms, particularly hyperactivity-impulsivity, in this sample. These findings are an important demonstration that the neuropsychological deficits and symptoms experienced by individuals diagnosed with ADHD during adulthood may not be negatively associated with telomere length.

[Accelerated telomere erosion in schizophrenia: A literature review]

Schizophrenia is associated with a weighted average of 14.5 years of potential life lost according to a recent meta-analysis. This is partly explained by high rates of suicide and a high prevalence of non-psychiatric comorbidity (cardiovascular diseases, diabetes, cancers…). However, all these causes could not fully explain the loss of life expectancy in people suffering from schizophrenia. Life expectancy has been strongly correlated with telomere length (TL). Telomeres are noncoding structures consisting of DNA TTAGGG tandem repeats and associated proteins located at the end of the chromosomes. Their role is to help preserve genome stability by protecting chromosomal ends from the loss of genetic material. The progressive loss of telomeric material during cell divisions has led researchers to consider telomeres as molecular clocks that measure the number of divisions left until cellular death. The fact that both shorter telomeres and schizophrenia have been associated with a decrease in life expectancy has fueled the interest in the study of TL in schizophrenia. In this article, after a detailed review of the literature on the relationships between telomere length and schizophrenia, we discuss the different pathophysiological mechanisms which might explain this association. Based on this analysis, in the last part of the article we discuss potential research, therapeutic and prevention prospects. To date, the majority of the studies and meta-analyses found a decrease in TL in subjects with schizophrenia compared to control subjects. Conversely, all the studies exploring the TL in subjects suffering from first episode psychosis (FEP) have shown no significant difference from TL in control subjects. This suggests that excessive shortening of telomeres occurs during the course of the disease, thus it seems more probable that schizophrenia (or processes associated with it) affects TL rather than telomere erosion being a cause of the disorder. Several pathophysiological, non-mutually exclusive mechanisms have been proposed to explain the observed data. A first hypothesis to explain the acceleration of the physiological process of telomere erosion in schizophrenia is the activation of inflammation processes and oxidative stress as a consequence of schizophrenia per se. However, it seems more probable that reduced TL may be a result of cumulative exposure to chronic stress related to schizophrenia. Indeed, in healthy individuals a growing body of evidence has linked chronic stress to accelerated shortening of TL. This might explain why telomere erosion is too small to be detected in FEP patients who are younger and have a shorter duration of illness than subjects with schizophrenia. Based on these both explanations, telomere alterations may be considered as a biomarker of illness progression and might be useful for illness staging. Identifying processes associated with TL reduction might improve our understanding of the increased mortality and morbidity in schizophrenia, improve reliability of diagnosis, and hopefully suggest means for prevention and/or treatment. Treatments that prevent exposure and/or vulnerability to stressful life events that ameliorate schizophrenia may also prevent or decelerate telomere erosion. In this perspective, engaging subjects suffering from schizophrenia in a healthy diet and regular activity could be both promising strategies to protect telomere maintenance and improve health span at old age. In addition, the inflammatory process and oxidative stress involved in the physiopathology in at least a subgroup of subjects with schizophrenia could also be responsible for telomere erosion. Thus, an efficient anti-inflammatory therapeutic approach that targets these specific pathways could be of interest in this subgroup to limit telomere erosion. Mindfulness-based stress reduction (MBSR) therapies have been shown to reduce telomere erosion by increasing telomerase activity, although these psychological therapies should be used carefully in psychosis. Finally, advancing our understanding of the relationship between stress, inflammation and TL is of great interest for psychiatric research and for understanding stress effects in this population.

Exploring genetic variants in obsessive compulsive disorder severity: A GWAS approach

BACKGROUND

The severity of Obsessive-Compulsive Disorder (OCD) varies significantly among probands. No study has specifically investigated the genetic base of OCD severity. A previous study from our group found an OCD polygenic risk score to predict pre- and post-treatment severity. This study explores the genomic bases of OCD severity.

METHODS

We administered the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) to 401 patients at their first visit to our clinic to measure their OCD severity. Genotyping data was collected by using the Infinium PsychArray-24 BeadChip kit (Illumina). We analyzed genetic association with OCD severity in a linear regression analysis at single-nucleotide polymorphism (SNP)- and gene-levels, this last also considering rare variants. Enrichment analyses were performed from gene-based analyses' results.

RESULTS

No SNP reached significant association (p < 10^-8) with the YBOCS. Six markers showed suggestive association (p < 10^-5). The top SNP was an intergenic variant in chromosome 2: rs7578149 (p < 1.89 × 10^-6), located in a region suggestively associated with MDD. Linkage disequilibrium was found for two clusters of SNPs located between SLC16A14 and SP110 in chromosome 2, all of them forming one peak of association. Enrichment analyses revealed OCD genes to be associated with porin activity (FDR = 0.01) and transmembrane structure (FDR = 0.04).

LIMITATIONS

The size of the sample and the transversal nature of the severity measure are limitations of this study.

CONCLUSION

This study contributes to better characterize OCD at an individual level, helping to know more about the prognosis of the disorder and develop more individualized treatments.

Season's Effects on Some Clinical, Hematological Parameters and Blood Cortisol Level in Sedated Arabian Horses With Xylazine

Influence of heat or cold stress in sedated animals is unclear and requires further investigations. The present study aimed to evaluate the season's effects on some clinical, hematological parameters and blood cortisol level in sedated Arabian horses with xylazine. Therefore, seven Arabian horses were used to investigate heart and respiratory rates, and capillary refill time and serum cortisol level were recorded before (0) and at 5, 15, 60, and 180 minutes postsedation. Heparinized venous samples were collected before (0) and 3 hours postsedation for analysis of hematological analysis. Arterial blood samples were collected before and 1 hour postsedation for arterial blood gases and electrolytes analysis. Repeated analysis of variance was performed (P < .05). Significant decreases have been observed in heart and respiratory rates at 5, 15, and 60 minutes postsedation in summer and only at 5 minutes postsedation in winter. Arterial oxygen pressure and arterial carbon dioxide pressure showed a significant decrease and increase, respectively at 1 hour postsedation in summer and winter. The serum cortisol levels were significantly higher in summer than in winter at 5, 15, and 60 minutes postsedation. In summer, the postsedation concentrations of cortisol did not change significantly than its values before sedation. However, in winter, the cortisol concentration decreased significantly at 5, 15, and 60 minutes postsedation compared with their value before sedation. The present study suggests that these season's effects on the sedated Arabian horses could take into consideration in xylazine-sedated Arabian horses.

The Possible Role of Telomere Length and Chemokines in the Aging Process: A Transdiagnostic Review in Psychiatry

Background:

Psychiatric disorders are common, reaching a worldwide prevalence of 29.2%. They are associated with a high risk of premature death and with accelerated aging in clinical, molecular and neuroimaging studies. Recently, there is strong evidence suggesting a possible role of telomere length and chemokines in aging processes in psychiatric disorders.

Objective:

We aimed to review the literature on telomere length and chemokines and its association with early aging in mental illnesses on a transdiagnostic approach.

Results:

The review highlights the association between psychiatric disorders and early aging. Several independent studies have reported shorter telomere length and dysregulations on levels of circulating chemokines in schizophrenia, bipolar disorder, major depressive disorder, and anxiety disorders, suggesting a complex interaction between these markers in a transdiagnostic level. However, studies have investigated the inflammatory markers and telomere shortening separately and associated with a particular diagnosis, rather than as a transdiagnostic biological feature.

Conclusion:

There is consistent evidence supporting the relationship between accelerated aging, telomere length, and chemokines in mental disorders, but they have been studied individually. Thus, more research is needed to improve the knowledge of accelerated senescence and its biomarkers in psychiatry, not only individually in each diagnosis, but also based on a transdiagnostic perspective. Moreover, further research should try to elucidate how the intricate association between the chemokines and telomeres together may contribute to the aging process in psychiatric disorders.

Paranoid schizophrenia and methamphetamine-induced paranoia are both characterized by a similar LINE-1 partial methylation profile, which is more pronounced in paranoid schizophrenia

BACKGROUND

There is evidence that schizophrenia is a neuro-immune disorder. Genes linked to intragenic LINE-1 methylation show a strong association with immune-associated disorders including psychosis. The aim of this study was to examine LINE-1 methylation patterns in paranoid schizophrenia and methamphetamine-induced paranoia, a model for schizophrenia.

METHODS

This study recruited 31 patients with paranoid schizophrenia, 94 with methamphetamine-induced paranoia (MIP) and 163 normal controls. LINE-1 methylation patterns were assayed in peripheral blood mononuclear cells and a combined bisulphite restriction analysis and COBRA were used to estimate LINE1 methylation (mC) and CpG dinucleotide methylation patterns, namely 2 methylated (mCmC) and 2 unmethylated (uCuC) CpGs and the partially methylated loci mCuC (5'm with 3'u) and uCmC (5'u with 3'm).

RESULTS

Patients with paranoid schizophrenia show highly significant changes in LINE-1 partial methylation patterns, namely a higher percentage of mCuC and lower percentage of uCmC as compared with controls and MIP patients, while the latter show a higher percentage of mCuC but lower percentage of uCmC as compared with controls. Higher mCuC significantly predicts paranoid schizophrenia with a sensitivity of 51.6%, specificity of 97.5% and an area under the ROC curve of 0.895.

CONCLUSIONS

The results indicate that a common dysfunction in LINE-1 partial methylation may underpin both paranoid schizophrenia and MIP and that this methylation pattern is significantly more expressed in paranoid schizophrenia than MIP. Reciprocal links between impairments in LINE-1 methylation and neuro-immune and neuro-oxidative pathways may underpin the pathophysiology of both MIP and paranoid schizophrenia.

Psychometric liability to psychosis and childhood adversities are associated with shorter telomere length: A study on schizophrenia patients, unaffected siblings, and non-clinical controls

Compared to the general population, individuals diagnosed with Schizophrenia (SCZ) experience a higher frequency and an earlier onset of chronic medical disorders, resulting in a reduction in life expectancy by an average of 15-25 years. Recently, it has been hypothesized that SCZ is a syndrome of accelerated aging. Childhood adversity was also associated with the pathogenesis and course of SCZ. Our hypothesis was that both SCZ patients and their unaffected siblings would have shorter telomere length (TL) compared to of non-clinical controls. Our additional goals were to determine (1) whether shorter TL correlates with intermediate phenotypes of SCZ (i.e. Psychosis-like symptoms and schizotypal traits); and (2) whether childhood adversities have a moderating role in TL shortening among SCZ and their unaffected siblings. To this end, SCZ patients (n = 100), their unaffected siblings (n = 100) and non-clinical controls (n = 100) were enrolled. The main variables were TL, measured by aTL-qPCR; psychotic-like and schizotypal symptoms, assessed by The Community Assessment of Psychic Experience (CAPE) and the Structured Interview for Schizotypy-Revised (SIS-R), respectively; and childhood adversities evaluated by the Childhood Experience of Care and Abuse (CECA)-Interview. Potentially relevant variables also included in the analyses were: Global Assessment of Functioning (GAF) scores, cognitive performance, and socio-demographic features. In contrast to our hypothesis patients had similar TL when compared to the non-clinical controls. Interestingly, unaffected siblings had longer TL compared to both patients and controls (p < 0.001). Independent from group status a negative correlation was observed between TL and psychotic-like symptoms as rated by the CAPE (p < 0.01). Childhood adversities, especially loneliness between ages 0 and 11 were also negatively associated with TL (p < 0.05). Our findings suggest that psychometric liability to psychosis and childhood adversities may be associated with shorter TL. Unaffected siblings had longer TL, suggesting the potential role of resilience on both the TL and the clinical presentation. These findings must be considered preliminary, calling for larger-scale replication efforts.

Telomere length is associated with childhood trauma in patients with severe mental disorders

Reduced telomere length (TL) and structural brain abnormalities have been reported in patients with schizophrenia (SZ) and bipolar disorder (BD). Childhood traumatic events are more frequent in SZ and BD than in healthy individuals (HC), and based on recent findings in healthy individuals could represent one important factor for TL and brain aberrations in patients. The study comprised 1024 individuals (SZ [n = 373]; BD [n = 249] and HC [n = 402]). TL was measured by quantitative polymerase chain reaction (qPCR), and childhood trauma was assessed using the Childhood Trauma Questionnaire (CTQ). Diagnosis was obtained by the Structured Clinical Interview (SCID) for the diagnostic and statistical manual of mental disorders-IV (DSM-IV). FreeSurfer was used to obtain regional and global brain volumes from T1-weighted magnetic resonance imaging (MRI) brain scans. All analyses were adjusted for current age and sex. Patients had on average shorter TL (F = 7.87, p = 0.005, Cohen's d = 0.17) and reported more childhood trauma experiences than HC (χ² = 148.9, p < 0.001). Patients with a history of childhood sexual, physical or emotional abuse had shorter TL relative to HC and to patients without a history of childhood abuse (F = 6.93, p = 0.006, Cohen's d = 0.16). After adjusting for childhood abuse, no difference in TL was observed between patients and HC (p = 0.12). There was no statistically significant difference in reported childhood abuse exposure or TL between SZ and BD. Our analyses revealed no significant associations between TL and clinical characteristics or brain morphometry. We demonstrate shorter TL in SZ and BD compared with HC and showed that TL is sensitive to childhood trauma experiences. Further studies are needed to identify the biological mechanisms of this relationship.

Telomeres in neurological disorders

Ever since their discovery, the telomeres and the telomerase have been topics of intensive research, first as a mechanism of cellular aging and later as an indicator of health and diseases in humans. By protecting the chromosome ends, the telomeres play a vital role in preserving the information in our genome. Telomeres shorten with age and the rate of telomere erosion provides insight into the proliferation history of cells. The pace of telomere attrition is known to increase at the onset of several pathological conditions. Telomere shortening has been emerging as a potential contributor in the pathogenesis of several neurological disorders including autism spectrum disorders (ASD), schizophrenia, Alzheimer's disease (AD), Parkinson's disease (PD) and depression. The rate of telomere attrition in the brain is slower than that of other tissues owing to the low rate of cell proliferation in brain. Telomere maintenance is crucial for the functioning of stem cells in brain. Taking together the studies on telomere attrition in various neurological disorders, an association between telomere shortening and disease status has been demonstrated in schizophrenia, AD and depression, in spite of a few negative reports. But, studies in ASD and PD have failed to produce conclusive results. The cause-effect relationship between TL and neurological disorders is yet to be elucidated. The factors responsible for telomere erosion, which have also been implicated in the pathogenesis of neurological disorders, need to be explored in detail. Telomerase activation is now being considered as a potential therapeutic strategy for neurological disorders.

Early Senescence and Leukocyte Telomere Shortening in SCHIZOPHRENIA: A Role for Cytomegalovirus Infection?

Schizophrenia is a severe, chronic mental disorder characterized by delusions and hallucinations. Several evidences support the link of schizophrenia with accelerated telomeres shortening and accelerated aging. Thus, schizophrenia patients show higher mortality compared to age-matched healthy donors. The etiology of schizophrenia is multifactorial, involving genetic and environmental factors. Telomere erosion has been shown to be accelerated by different factors including environmental factors such as cigarette smoking and chronic alcohol consumption or by psychosocial stress such as childhood maltreatment. In humans, telomere studies have mainly relied on measurements of leukocyte telomere length and it is generally accepted that individuals with short leukocyte telomere length are considered biologically older than those with longer ones. A dysregulation of both innate and adaptive immune systems has been described in schizophrenia patients and other mental diseases supporting the contribution of the immune system to disease symptoms. Thus, it has been suggested that abnormal immune activation with high pro-inflammatory cytokine production in response to still undefined environmental agents such as herpesviruses infections can be involved in the pathogenesis and pathophysiology of schizophrenia. It has been proposed that chronic inflammation and oxidative stress are involved in the course of schizophrenia illness, early onset of cardiovascular disease, accelerated aging, and premature mortality in schizophrenia. Prenatal or neonatal exposures to neurotropic pathogens such as Cytomegalovirus or Toxoplasma gondii have been proposed as environmental risk factors for schizophrenia in individuals with a risk genetic background. Thus, pro-inflammatory cytokines and microglia activation, together with genetic vulnerability, are considered etiological factors for schizophrenia, and support that inflammation status is involved in the course of illness in schizophrenia.

Longer telomeres in elderly schizophrenia are associated with long-term hospitalization in the Japanese population

Several previous studies have investigated an association between leukocyte telomere length (LTL) and schizophrenia (SCZ). However, results have been largely inconsistent, partially due to the relatively small sample sizes in each study and heterogeneity caused by various uncontrolled confounders (e.g., duration of illness or hospitalization, lifetime antipsychotic dose, and LTL assay methods). Here, we investigate the association of LTL with SCZ with the quantitative polymerase chain reaction method in independent cohorts consisting of 1241 patients with SCZ and 1042 controls (the largest independent sample in this field). Furthermore, we examined whether duration of hospitalization and lifetime antipsychotic dose had an effect on LTL in SCZ. In all samples, we observed significantly longer LTL in patients with SCZ relative to controls. In subgroup analyses, we observed that longer telomeres in SCZ were only visible in elderly patients and not in patients under 50 years old. Moreover, significantly longer LTL in elderly patients with SCZ was only specific to those with long-term hospitalization, but not outpatients or those with short-term hospitalization. This may be because the former received more appropriate lifestyle management. Meanwhile, lifetime antipsychotic dose had no effect on LTL. Our findings suggest that consideration of the effect of age and duration of hospitalization on LTL may improve our understanding of controversial results obtained in previous studies of telomeres in SCZ.