Meta-analysis of associations between tumor necrosis factor-α polymorphisms and schizophrenia susceptibility

Association between Tumor Necrosis factor-Alpha(TNF-a) polymorphisms and Schizophrenia: an updated meta-analysis

BACKGROUND

Previous studies have explored associations between Tumour Necrosis factor-Alpha (TNF-a) polymorphisms and Schizophrenia. Their results were controversial. We conducted a meta-analysis to clarify the association between TNF-a - 308 G/A(rs1800629), -1031T/C(rs1799964), -863C/A(rs1800630) and -857 C/T (rs1799724) polymorphisms and Schizophrenia.

METHODS

All the studies that investigated the association between TNF-a polymorphisms and Schizophrenia published before 15 October 2020 were included in. The literature were comprehensively searched and identified in 2 English databases and 2 Chinese databases. The odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated.

RESULTS

For -1031 T/C polymorphism, at the overall analysis, significantly decreased Schizophrenia risk was found in T allele in the allele model (p = 0.006, OR = 0.88) and increased Schizophrenia risk was found in TC + CC genotype in the dominant model (p = 0.005, OR = 1.17). Similarly, the same results were obtained when pooled analyses were included in high-quality studies (allele model: p = 0.005, OR = 0.86; dominant model: p = 0.007, OR = 1.20). In addition, when stratified by ethnicity, the results showed that in allele model, the T allele decreased Schizophrenia risk in East Asian (p = 0.031, OR = 0.90).

CONCLUSION

The association may most likely result from less-credible, rather than from true associations or biological factors on the TNF-a - 1031 T/C polymorphism with Schizophrenia risk.KeypointsFor -1031T/C polymorphism, at the overall analysis, significantly decreased schizophrenia risk was found in T allele in the allele model, and increased schizophrenia risk was found in TC + CC genotype in the dominant model.In allele model, the T allele decreased schizophrenia risk in East Asian when stratified by ethnicity, and in the dominant model, TC + CC genotype increased schizophrenia risk in East Asian.

Tumor necrosis factor-alpha -1031T/C polymorphism is associated with cognitive deficits in chronic schizophrenia patients versus healthy controls

Recent compelling research has demonstrated a pathophysiologic role for proinflammatory cytokines of microglial origin in decreasing neurocognitive function. Psychiatric diseases are already known to have reduced cognitive function and are also associated with increased inflammation. To elaborate on these data, our study aims to investigate how a particular polymorphism of the tumor necrosis factor gene, TNF-α -1031T/C, affects neurocognitive performance in patients with schizophrenia. We recruited 905 patients with schizophrenia and 571 healthy control subjects. We employed the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) to test for neurocognitive function and the positive and negative syndrome scale to evaluate schizophrenia severity. The -1031T/C polymorphism was genotyped in both healthy controls and schizophrenic patients. Our results demonstrate that patients with the C allele (either T/C or C/C) possessed increased immediate memory index, visuospatial/constructional index, and RBANS total scores as compared to patients without it (p < .05). In healthy controls, there was no significant difference across genotypes (p > .05). Our findings demonstrate that the TNF-α -1031T/C polymorphism may not play a role in the susceptibility of schizophrenia itself, but may be involved in the cognitive deficits of schizophrenia. This suggests an important role for cytokine signaling in mediating the severity of cognitive dysfunction in schizophrenia.

Interaction between BDNF and TNF-α genes in schizophrenia

OBJECTIVE

Our recent work reported that tumor necrosis factor-α (TNF-α) is negatively correlated with brain-derived neurotrophic factor (BDNF) in patients with schizophrenia. A previous study has shown that TNF-α could regulate the extracellular secretion of BDNF. Therefore, we hypothesized that the TNF-α gene (TNF-α) may interact with the BDNF gene (BDNF) to influence schizophrenia risk.

METHODS

We recruited 694 patients with schizophrenia from three mental hospitals in Eastern China and 725 healthy controls. The Positive and Negative Syndrome Scale (PANSS) was employed to evaluate symptom severity. The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was performed to assess cognitive function. The SNPs rs6265 in BDNF and rs1799964 in TNF-α were genotyped.

RESULTS

There were no significant differences in allele and genotype frequencies in either rs6265 or rs1799964 between the case and control groups. A significant association of rs6265 AA + AG × rs1799964 CC + CT with schizophrenia was observed (OR = 1.14, 95%CI: 1.02-1.27; P = .02). There were significant differences in the RBANS attention and total scores between the patients with rs6265A and rs1799964C alleles and those without these two alleles (P = .03 and P = .03 after Bonferroni correction, respectively).

CONCLUSION

Our findings provided preliminary evidence that the interaction of BDNF and TNF-α may confer susceptibility to schizophrenia and cognitive dysfunction.