A Peptide Found in Schizophrenia and Autism Causes Behavioral Changes in Rats

In a previous study we showed that β-casomorphin-7 (β-CM7) is taken up by brain regions relevant to schizophrenia and autism. The present experiment was designed to find whether β-CM7 has any behavioral or analgesic effects in rats. About 65 seconds after treatment with different doses of β-CM7, rats became restless and ran violently, with teeth chattering and with rapid respiration. Seven minutes later, the rats became inactive with less walking, distancing themselves from the other rat in the same cage, and sitting in, or putting their head against, the corner of the cage. The sound response was reduced and social interaction was absent. One hour later, the rats showed hyperdefensiveness. The above behavioral effects of β-CM7 did not occur when rats were pretreated with naloxone (2 mg/kg, IP). The rats receiving saline did not show any behavioral changes throughout the 2 hour period of observation. β-CM7 also demonstrated analgesic effects, which could be blocked by naloxone. The results suggest that β-CM7 may play a role in behavioral disorders such as autism and schizophrenia.

β-Casomorphin Induces Fos-Like Immunoreactivity in Discrete Brain Regions Relevant to Schizophrenia and Autism

The induction of Fos-like immunoreactivity (FLI) was used to determine the brain localization affected by b-casomorphin-7 (b-CM7). Peripheral administration of human b-CM7 at different doses (5, 10 and 30 mg/kg, IV for 1 hour) to rats induced moderate to strong FLI in discrete brain regions including the nucleus accumbens, caudate putamen, ventral tegmental and median raphe nucleus, and orbitofrontal, prefrontal, parietal, temporal, occipital and entorhinal cortex. All of the above areas have been shown to be altered either functionally or anatomically in patients with schizophrenia, and most have been shown to be functionally abnormal in autism. Some of these brain areas are originators or components of dopaminergic, serotoninergic and GABA-ergic pathways, suggesting that b-CM7 can affect the function of all of these systems. The role of some other affected areas in emotional and motivated behavior, social adaptation, hallucinations and delusions suggests that b-CM7, which was found in high concentration in the CSF, blood and urine of patients with either schizophrenia or autism, may be relevant to schizophrenia and autism. Induction of FLI in the above brain areas by a moderate dose (10 mg/kg) of b-CM7 was attenuated significantly, or blocked, by pretreatment with naloxone (2 mg/kg, IP). It is concluded that human b-CM7 can cross the blood-brain barrier, activate opioid receptors and affect brain regions similar to those affected by schizophrenia and autism.

IgG dynamics of dietary antigens point to cerebrospinal fluid barrier or flow dysfunction in first-episode schizophrenia

Schizophrenia is a complex brain disorder that may be accompanied by idiopathic inflammation. Classic central nervous system (CNS) inflammatory disorders such as viral encephalitis or multiple sclerosis can be characterized by incongruent serum and cerebrospinal fluid (CSF) IgG due in part to localized intrathecal synthesis of antibodies. The dietary antigens, wheat gluten and bovine milk casein, can induce a humoral immune response in susceptible individuals with schizophrenia, but the correlation between the food-derived serological and intrathecal IgG response is not known. Here, we measured IgG to wheat gluten and bovine milk casein in matched serum and CSF samples from 105 individuals with first-episode schizophrenia (n=75 antipsychotic-naïve), and 61 controls. We found striking correlations in the levels of IgG response to dietary proteins between serum and CSF of schizophrenia patients, but not controls (schizophrenia, R(2)=0.34-0.55, p⩽0.0001; controls R(2)=0.05-0.06, p>0.33). A gauge of blood-CSF barrier permeability and CSF flow rate, the CSF-to-serum albumin ratio, was significantly elevated in cases compared to controls (p⩽0.001-0.003). Indicators of intrathecal IgG production, the CSF IgG index and the specific Antibody Index, were not significantly altered in schizophrenia compared to controls. Thus, the selective diffusion of bovine milk casein and wheat gluten antibodies between serum and CSF in schizophrenia may be the function of a low-level anatomical barrier dysfunction or altered CSF flow rate, which may be transient in nature.

Towards a possible aetiology for depressions?

BACKGROUND

Since a genetic disposition for depression is probable, there ought to be biochemical changes. Increased peptide levels with relevant bioactivities have been found in urine in a previous investigation, which may be such changes.

METHODS

Urine from patients with severe depression according to ICD 10 have been run on reversed phase High Performance Liquid Chromatography, and off line mass spectrometry was performed on some of these peptides.

RESULTS

We find overlapping patterns of peptide peaks in severe depression, but with considerable individuality. Mass spectrometry shows that some of these peptides are probably of dietary origin, because their sequences are found only in certain dietary proteins. Opioids from casein and gliadin are typical examples.

CONCLUSION

Our data show that the disposition must be polygenetic because some peptide peaks with the same bioactivity are of different length in different patients, but with the same diagnosis. However, some of the peaks are common Peptide increase in urine is found when break down is deficient, and the data presented agree with reports on peptidase deficiencies in depression. Antidepressant drugs decrease the peptide level after about 3 weeks.

Could schizophrenia be reasonably explained by Dohan's hypothesis on genetic interaction with a dietary peptide overload?

1. Dohan has proposed that schizophrenia is a genetic disposition which interacts with an overload of dietary proteins such as casein and gluten or gliadin. 2. A systematic attempt is made to see if this hypothesis is possible faced with aspects of schizophrenia that must be accounted for. 3. The authors conclusion is that it is possible, but more serious work in this field is urgently needed.

Decreased urinary peptide excretion in schizophrenic patients after neuroleptic treatment

Six schizophrenic patients had their urinary peptide levels measured before and after 5 weeks of treatment with neuroleptic medications. For two patients, levels were also measured after a reduction in the neuroleptic dose. Because of the heterogeneity of peptide peaks with the same bioactivity, the overall peptide levels were compared to initial levels. A neuroleptic effect on peptide levels was demonstrated. Several research groups have reported enzyme induction caused by neuroleptics in vivo.

Specific IgA antibody increases in schizophrenia

IgA antibody levels in serum were examined in two groups of schizophrenic patients. All were diagnosed according to DSM-III-R criteria. One group of 36 males and 12 females were compared to historical controls. The other group consisted of 13 males off drugs for at least 3 months; these were compared with age- and sex-matched controls. An increase in specific IgA antibodies was found. More schizophrenics than controls showed IgA antibody levels above the upper normal limit to gliadin, beta-lactoglobulin, and casein.

Urinary chromatographic profiles in schizophrenia

In a series of articles, Trygstad et al. (1980) suggested that specific patterns of peptide excretion and increased levels of peptide material are found by chromatographic analysis of the urine of patients with a variety of psychiatric illness including schizophrenia. As these results have not been independently replicated in another laboratory, we conducted an investigation of urine samples from 5 DSM-III classified schizophrenic patients and 4 normal subjects using the techniques described by the Norwegian group, and with a series of modifications. The chromatographic profiles obtained differ widely from those reported by Trygstad et al. No significant differences were detected between patients with schizophrenia and controls. The methods used by Trygstad et al. are complex and we have defined several parts of the methods which are subject to variability. Our findings lend no support to the view that patients with psychiatric illness can be readily distinguished from normal subjects by the amount or profile of peptide excretion in urine.