Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2017 Apr 10:13:1057-1063.
doi: 10.2147/NDT.S126979. eCollection 2017.

Clinical and biochemical study of d-serine metabolism among schizophrenia patients

Hamdy N El-Tallawy  1 , Tahia H Saleem  2 , Abdallah Maa El-Ebidi  3 , Mohammed H Hassan  4 , Romany H Gabra  1 , Wafaa Ma Farghaly  1 , Nagwa Abo El-Maali  5 , Hoda S Sherkawy  3
Affiliations

Clinical and biochemical study of d-serine metabolism among schizophrenia patients

Hamdy N El-Tallawy et al. Neuropsychiatr Dis Treat. .

Abstract

Background: Schizophrenia is a typical N-methyl-d-aspartate receptor (NMDA-R) hypofunction disorder. Decreased d-serine (d-Ser) levels in the periphery occur in schizophrenia and may reflect decreased availability of d-Ser to activate NMDA-R in the brain.

Objective: The objective of this study was to investigate the role of d-Ser metabolism in the pathogenesis of schizophrenia via biochemical assays and correlates, the serum level of d-Ser, d-serine racemase (SR) (responsible for its formation from l-serine [l-Ser]) and d-amino acid oxidase (DAAO) (responsible for its catabolism), among different clinical types of schizophrenia patients.

Patients and methods: This cross-sectional case-control study was carried out on 100 patients and 50 controls. They were recruited from the outpatients' psychiatric unit of the Neuropsychiatric Department of Assiut University Hospital, Upper Egypt. The type of schizophrenia was determined according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), while the severity of schizophrenia was determined according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Serum d-Ser levels were estimated using high-performance liquid chromatography (HPLC), while serum SR and DAAO were measured using commercially available enzyme-linked immunosorbent assay kits.

Results: There were significantly lower mean serum levels of d-Ser and SR and significantly higher mean serum levels of DAAO (P-value <0.01 for each) among schizophrenia patients when compared with the control group. Paranoid schizophrenia had the highest frequency, with a significantly lower serum levels of d-Ser and SR in the residual type and significantly higher serum levels of DAAO in undifferentiated and catatonic types. Combined receiver-operating characteristic curve for serum d-Ser, SR and DAAO indicated that the best serum level cutoff points at which schizophrenia manifestations started to appear were ≤ 61.4 mg/L for d-Ser, ≤ 15.5 pg/mL for SR and >35.6 pg/mL for DAAO.

Conclusion: The present study confirms that disturbed d-Ser metabolism could be implicated in the pathogenesis of schizophrenia.

Keywords: D-amino acid oxidase; D-serine; HPLC; schizophrenia; serine racemase.

PubMed Disclaimer

Conflict of interest statement

Disclosure The authors report no conflicts of interest in this work.

Figures

Figure 1
Figure 1
Comparison between the mean serum levels of d-Ser, SR and DAAO among schizophrenia patients versus the control group. Abbreviations: d-Ser, d-serine; SR, d-serine racemase; DAAO, d-amino acid oxidase.
Figure 2
Figure 2
Correlation of the serum levels of d-Ser and SR among schizophrenia patients showing a positive correlation. Abbreviations: d-Ser, d-serine; SR, d-serine racemase.
Figure 3
Figure 3
Correlation of the serum levels of d-Ser and DAAO among schizophrenia patients showing a negative correlation. Abbreviations: d-Ser, d-serine; DAAO, d-amino acid oxidase.
Figure 4
Figure 4
Correlation of the serum levels of DAAO and SR among schizophrenia patients showing a negative correlation. Abbreviations: DAAO, d-amino acid oxidase; SR, d-serine racemase.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Northoff G. Resting state activity and the “stream of consciousness” in schizophrenia – neurophenomenal hypotheses. Schizophr Bull. 2015;41(1):280–290. - PMC - PubMed
    1. Collin L, Bindra J, Raju M, Gillberg C, Minnis H. Facial emotion recognition in child psychiatry: a systematic review. Res Dev Disabil. 2013;34(5):1505–1520. - PubMed
    1. Anticevic A, Murray JD, Barch DM. Bridging levels of understanding in schizophrenia through computational modeling. Clin Psychol Sci. 2015;3(3):433–459. - PMC - PubMed
    1. Elvevag B, Goldberg TE. Cognitive impairment in schizophrenia is the core of the disorder. World Health Report 2001. Mental health: new understanding, new hope. Geneva: World Health Organization. Crit Rev Neurobiol. 2000;14(1):1–21. - PubMed
    1. Javitt DC. Twenty-five years of glutamate in schizophrenia: are we there yet? Schizophr Bull. 2012;38(5):911–913. - PMC - PubMed