Developmental expression of dysbindin in Muller cells of rat retina

Exploring the role of macular thickness as a potential early biomarker of neurodegeneration in acute schizophrenia

OBJECTIVE

The retina has been investigated as a gateway to assess the neurodegenerative changes in the brain. Schizophrenia is also conceptualized as a neurodegenerative disorder like Alzheimer's and Parkinson's disease. The current literature suggests reduced retinal nerve fibre layer (RNFL) thickness and macular thickness (MT), as a marker of neurodegeneration, in patient suffering from chronic schizophrenia. This study aims to compare RNFL thickness and MT in acute schizophrenic patients with age and sex matched healthy controls.

METHODS

Twenty acutely ill schizophrenic patients and 20 normal controls were included in the study after proper informed consent. RNFL thickness and MT was measured using spectral domain Optical Coherence Tomography after clinical psychological assessment and ocular examination.

RESULTS

The two groups were comparable in terms of socio-demographic variables. The average RNFL thickness of patients and healthy controls was 102.11 ± 29.18 µm and 105.14 ± 27.35 µm, respectively. Central macular thickness was 181.12 ± 13.63 µm in patients and 234.58 ± 10.71 µm in controls. There was a statistically significant reduction in thickness of macula (p < 0.05) but not for RNFL (p = 0.339).

CONCLUSION

The study concludes that macular thinning rather than reduced RNFL is an early manifestation in acute schizophrenia patients and can be considered as a potential early biomarker of neurodegeneration in schizophrenia.

Sex-dimorphic effects of biogenesis of lysosome-related organelles complex-1 deficiency on mouse perinatal brain development

The function(s) of the Biogenesis of Lysosome-related Organelles Complex-1 (BLOC-1) during brain development is to date largely unknown. Here, we investigated how its absence alters the trajectory of postnatal brain development using as model the pallid mouse. Most of the defects observed early postnatally in the mutant mice were more prominent in males than in females and in the hippocampus. Male mutant mice, but not females, had smaller brains as compared to sex-matching wild types at postnatal day 1 (P1), this deficit was largely recovered by P14 and P45. An abnormal cytoarchitecture of the pyramidal cell layer of the hippocampus was observed in P1 pallid male, but not female, or juvenile mice (P45), along with severely decreased expression levels of the radial glial marker Glutamate-Aspartate Transporter. Transcriptomic analyses showed that the overall response to the lack of functional BLOC-1 was more pronounced in hippocampi at P1 than at P45 or in the cerebral cortex. These observations suggest that absence of BLOC-1 renders males more susceptible to perinatal brain maldevelopment and although most abnormalities appear to have been resolved in juvenile animals, still permanent defects may be present, resulting in faulty neuronal circuits, and contribute to previously reported cognitive and behavioral phenotypes in adult BLOC-1-deficient mice.

Retinal Layer Abnormalities as Biomarkers of Schizophrenia

OBJECTIVE

Schizophrenia is associated with several brain deficits, as well as visual processing deficits, but clinically useful biomarkers are elusive. We hypothesized that retinal layer changes, noninvasively visualized using spectral-domain optical coherence tomography (SD-OCT), may represent a possible "window" to these abnormalities.

METHODS

A Leica EnvisuTM SD-OCT device was used to obtain high-resolution central foveal B-scans in both eyes of 35 patients with schizophrenia and 50 demographically matched controls. Manual retinal layer segmentation was performed to acquire individual and combined layer thickness measurements in 3 macular regions. Contrast sensitivity was measured at 3 spatial frequencies in a subgroup of each cohort. Differences were compared using adjusted linear models and significantly different layer measures in patients underwent Spearman Rank correlations with contrast sensitivity, quantified symptoms severity, disease duration, and antipsychotic medication dose.

RESULTS

Total retinal and photoreceptor complex thickness was reduced in all regions in patients (P < .0001). Segmentation revealed consistent thinning of the outer nuclear layer (P < .001) and inner segment layer (P < .05), as well as a pattern of parafoveal ganglion cell changes. Low spatial frequency contrast sensitivity was reduced in patients (P = .002) and correlated with temporal parafoveal ganglion cell complex thinning (R = .48, P = .01). Negative symptom severity was inversely correlated with foveal photoreceptor complex thickness (R = -.54, P = .001) and outer nuclear layer thickness (R = -.47, P = .005).

CONCLUSIONS

Our novel findings demonstrate considerable retinal layer abnormalities in schizophrenia that are related to clinical features and visual function. With time, SD-OCT could provide easily-measurable biomarkers to facilitate clinical assessment and further our understanding of the disease.