Effects of thiamine administration on hypothermia and hypothalamic histamine levels in dietary-induced thiamine deficient rats

Profiling plasma levels of thiamine and histamine in Jordanian children with autism spectrum disorder (ASD): potential biomarkers for evaluation of ASD therapies and diet

BACKGROUND

The current work involved monitoring two biomarkers in the plasma of children with ASD: the cofactor thiamine that is involved in neurotransmitters modulation for acetylcholine, and the compound histamine, which acts as a neuromodulator by regulating the release of other neurotransmitters. This is the first report to highlight the potential utilization of plasma levels of the selected two brain-related biomarkers in children with ASD.

METHODS

A total of 43 children with ASD of both genders (age 4-12 years) were involved in this study and compared to age and gender-matched control children (n = 42). The diagnosis of ASD was based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM5), followed by an additional assessment using the Childhood Autism Rating Scale (CARS). All participants were Jordanian children on Mediterranean diet, and had no history of chronic illness or medications. Measurement of thiamine and histamine in plasma was performed using enzyme-linked immunosorbent assay (ELISA).

RESULTS

The outcomes revealed that average histamine levels (31.7 ± 18.5 ng/ml) of ASD group were 5.3× higher (p < .001) compared to their control (0.013 ± 0.011 ng/ml; 6.03 ± 4.25 ng/ml), while thiamine (10.78 ± 7.49 ng/ml) levels of ASD group were significantly lower (p < .001) than the control (37.92 ± 26.87 ng/ml; 0.209 ± 0.054 ng/ml).

CONCLUSIONS

The study is proposing that monitoring of the plasma levels of thiamine and histamine as biomarkers for future evaluation and development of ASD therapies and nutritious diets.

Role of thiamine in Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia in elderly individuals and is associated with progressive neurodegeneration of the human neocortex. Thiamine levels and the activity of thiamine-dependent enzymes are reduced in the brains and peripheral tissues of patients with AD. Genetic studies have provided the opportunity to determine what proteins link thiamine to AD pathology (ie, transketolase, apolipoprotein E, α-1-antitrypsin, pyruvate dehydrogenase complex, p53, glycogen synthetase kinase-3β, c-Fos gene, the Sp1 promoter gene, and the poly(ADP-ribosyl) polymerase-1 gene). We reviewed the association between histopathogenesis and neurotransmitters to understand the relationship between thiamine and AD pathology. Oral thiamine trials have been shown to improve the cognitive function of patients with AD; however, absorption of thiamine is poor in elderly individuals. In the early stage of thiamine-deficient encephalopathy (Wernicke's encephalopathy), however, parental thiamine has been used successfully. Therefore, further studies are needed to determine the benefits of using parental thiamine as a treatment for AD.

Behavioral and neurochemical alterations following thiamine deficiency in rodents: relationship to functions of cholinergic neurons

Memory deficits are induced during the late stage (20-25 days) of thiamine-deficient (TD) feeding. In this review, the role of cholinergic neurons on the memory deficit induced by TD feeding are summarized. Although memory deficit cannot be suppressed by an injection of thiamine once it appears, such impairment was found to be protected by early treatment with thiamine during TD feeding. Administration of muscarinic M(1) agonist McN-A-343 reversed the memory deficit observed in TD mice, although the muscarinic M(2) antagonist methoctramine did not. The "kampo" (traditional herbal) medicine, "kami-untan-to" (KUT), protected against the memory deficit observed in TD mice. Choline acetyltransferase (ChAT) fluorescence intensity, a marker of presynapse of cholinergic neurons, was decreased in the cortex and hippocampus at an early stage (14th day) of TD, and it was decreased in a wide range of brain areas at a late stage (25th day) of TD. Early KUT treatment inhibited the reduction of ChAT in the hippocampus of TD mice. These findings suggested that the memory deficit may be caused by a reduction in the cholinergic function at an early stage of TD, and that the activation of cholinergic neurons may play an important role in the improvement of TD-induced memory deficit.

Assay and biological relevance of endogenous histamine and its metabolites: application of microseparation techniques

This review provides an overview of the assay methods used to determine the presence of endogenous histamine (HA) including its metabolites, and also discusses their biological significance. Firstly, this review briefly summarizes the biological significance of HA and its biological pathways. Next, the assay methods with microseparation techniques, such as gas-chromatography (GC), liquid-chromatography (LC), capillary electrophoresis (CE) and capillary electrochromatography (CEC) are looked at from a developmental viewpoint. Finally, the use of these methods, including flow cytometry techniques, for the determination of HA and its metabolites in biological samples, such as blood, urine, brain and cells, is described. The merits and demerits associated with each of these various methods are also discussed, along with their applications.

Depletion of brain histamine produces regionally selective protection against thiamine deficiency-induced lesions in the rat

Breakdown of the blood brain barrier and the subsequent accumulation of free radicals, lactate, and glutamate appear to be the immediate causes of thiamine deficiency (TD)-induced damage to thalamus. The mechanisms triggering these events are unknown but recent evidence suggests an important role of histamine. We therefore studied the effects of histamine depletion on thalamic lesions in the pyrithiamine-induced thiamine deficient (PTD) rat. Chronic intracerebroventricular (i.c.v., 7 days) infusion of alpha-fluoromethylhistidine (FMH), combined with bilateral ibotenate destruction of the histamine-containing neurons in the tuberomammillary (TM) nucleus and bolus i.c.v. infusion of 48/80, a potent mast cell degranulating agent, was used to deplete brain histamine levels. PTD rats receiving combined FMH + 48/80 + TM lesions developed acute neurological symptoms, including spontaneous seizures, approximately 1 day earlier than PTD rats treated with i.c.v. infusion of vehicle and sham lesions of the TM. When examined 1 week after restoration of thiamine, the PTD vehicle + sham lesion animals contained severe neuronal loss and gliosis in midline, intralaminar, ventral, lateral, and posterior nuclei. PTD animals treated with FMH + 48/80 + TM lesions had little evidence of neuronal loss or microglial proliferation in thalamus except in the gelatinosus and anteroventral nuclei, in which there was complete neuronal loss. These data demonstrate a significant and regionally selective role of histamine in the development of thalamic lesions in a rat model of Wernicke's encephalopathy. Furthermore, these data suggest either a dissociation between seizures and thalamic lesions or a significant role of histamine in seizure-related damage to the thalamus.

Immunohistochemical estimation of brain choline acetyltransferase and somatostatin related to the impairment of avoidance learning induced by thiamine deficiency

We have found that thiamine-deficient (TD) rats show significant impairment of avoidance learning on the 25th day after the start of TD diet, as measured by passive-avoidance task. Administration of physostigmine (0.1 mg/kg, i.p.) from the 14th day after the start of TD diet improved the impairment of avoidance learning to the pair-fed (PF) control level by the 25th day. However, the recovery effect of physostigmine did not occur on the 25th day when the treatment was begun on the 21st day. To ascertain the correlation between the cholinergic neuronal function in rat brain and the avoidance learning impairment induced by TD, the immunohistochemical distribution of brain choline acetyltransferase (ChAT) was determined by fluorescence intensity using two-dimensional microphotometry. The intensity of the ChAT fluorescence started to decrease in the cortex and hippocampus on the 14th day and showed a marked decrease in the cortex, hippocampus and thalamus on the 25th day of TD feeding in comparison with PF controls. The intensity of the somatostatin (SST) fluorescence was unchanged on the 14th day of TD feeding, but on the 25th day, SST was significantly decreased in comparison with PF controls. Furthermore, physostigmine treatment from 14th day after the start of TD diet reversed SST fluorescence intensity to the control level by the 25th day. These results suggest that the impairment of avoidance learning induced by TD may involve not only cholinergic but also somatostatinergic systems.

Increased histamine release and granulocytes within the thalamus of a rat model of Wernicke's encephalopathy

The current study examined the possible role of increased histamine release and granulocyte activity in the vascular changes that precede the onset of necrotic lesions with the thalamus of the pyrithiamine-induced thiamine deficiency (PTD) rat model of Wernicke's encephalopathy (WE). An increase in histamine release and the number of granulocytes was observed in lateral thalamus on day 9 and in medial thalamus on day 10 of PTD treatment, a duration of thiamine deficiency associated with perivascular edema in this brain region. Within the hippocampus, histamine release was significantly increased on day 9, declined to control levels on days 10-12, and was significantly elevated on days 12-14. No granulocytes were observed in hippocampus of either PTD or control rats. These observations suggest that the release of histamine from nerve terminals and histamine and other vasoactive substances from granulocytes may be responsible for thiamine deficiency-induced vascular breakdown and perivascular edema within thalamus.

Immunohistochemical estimation of rat brain somatostatin on avoidance learning impairment induced by thiamine deficiency

In rats, on the 25th day after the start of a thiamine-deficient (TD) diet, impairment of avoidance learning was significantly induced in proportion to the decrease somatostatin (SST) fluorescence intensity in the cortex, amygdala, thalamus, hypothalamus, and hippocampus, including the CA1, CA2, and dentate gyrus (DG). Only a single injection of thiamine HCl (0.5 mg/rat, subcutaneous) on the 14th day after the start of a TD diet improved the amnesia to the level of the pair-fed control and prevented the decrease in the SST level. Whereas these reversal effects of thiamine treatment were not found when the treatment was given on the 21st day after the start of a TD diet. These results indicate that, after a certain degree of thiamine deficiency, TD-induced behavioral effects might be reversible, but some neuronal fibers might be irreversibly damaged, probably due to the reduction of thiamine-dependent enzymes in brain mitochondria. The results also suggest the possibility that SST in the brain may be closely related to the avoidance learning impairment induced by TD.

Thiamine deficiency-induced disruptions in the diurnal rhythm and regulation of body temperature in the rat

In the present study, diurnal rhythm and regulation of body temperature were monitored during and several weeks following pyrithiamine-induced thiamine deficiency (PTD group, n=8) or pairfeeding (control group, n=9). A significant decline of core body temperature and a disruption of its diurnal rhythm were observed at varying stages of PTD treatment. Following thiamine administration and return to thiamine-fortified chow, body temperature continued to fall and several days transpired before body temperature and its diurnal rhythm were returned to normal. When exposed to warm and cold environments, no significant group differences were observed in either the maximum temperature change or the time elapsed to reach maximal temperature change. Histological examination revealed necrotic lesions in thalamus and mammillary body in the PTD group characteristic of Wernicke's encephalopathy. No significant damage was observed in the medial preoptic and suprachiasmatic nuclei, brain regions involved in the regulation of body temperature and circadian rhythm. These findings suggest that hypothermia and disruption of the diurnal rhythm of body temperature can be reversed by restoration of adequate thiamine levels and are related to biochemical and physiological disturbances rather than gross structural changes.

Histamine-mediated neuronal death in a rat model of Wernicke's encephalopathy

Three experiments were conducted to examine the role of histamine in neuronal degeneration in a rat model of Wernicke's encephalopathy induced by an acute bout of pyrithiamine-induced thiamine deficiency (PTD). In the first experiment, histamine levels in medial thalamus of freely moving PTD rats measured by microdialysis were increased (180% of controls) at a prelesion stage of thiamine deficiency (treatment day 12) and further elevated 48 hr later (380%) in the same animals when necrosis was evident. Histamine levels in dialysates of the hippocampus collected simultaneously from the same animals were unchanged at either stage of thiamine deficiency. Glutamate levels in microdialysates from the same animals were unchanged at the prelesion stage but were significantly elevated on the second collection day. In a second experiment, separate groups of PTD and pairfed control (CT) rats were infused continuously with either alpha-fluoromethylhistidine (FMH; 80 mg/day, i.p.), an irreversible inhibitor of histamine synthesis, or saline. FMH pretreatment produced a significant protection against PTD-induced neuronal loss within the midline-intralaminar and anteromedial thalamic nuclei, but had no effect on damage to ventrolateral nuclei, anteroventral nucleus, or the mammillary bodies. In a third study, histamine (80 micrograms, free base) or vehicle was directly infused into the same region of medial thalamus dialyzed in experiment 1. Histamine infusion into prelesion PTD but not CT animals resulted in severe neuronal loss and gliosis. Infusion of vehicle into the same regions of PTD and CT rats produced a mild gliosis restricted to the needle tract with no evidence of neuronal loss. These observations together with recent evidence of a histamine enhancement of glutamate receptor activation suggest that early histamine release may contribute significantly to glutamate-N-methyl-D-aspartate (NMDA)-mediated excitotoxic neuronal death in thiamine deficiency-induced Wernicke's encephalopathy.

Extracellular glutamate is increased in thalamus during thiamine deficiency-induced lesions and is blocked by MK-801

The current study measured extracellular fluid (ECF) levels of excitatory amino acids before and during the onset of thiamine deficiency-induced pathologic lesions. Male Sprague-Dawley rats were treated with daily pyrithiamine (0.25 mg/kg i.p.) and a thiamine-deficient diet (PTD). Microdialysates were simultaneously collected from probes inserted acutely via guide cannulae into right paracentral and ventrolateral nuclei of thalamus and left hippocampus of PTD and pair-fed controls. Hourly samples were collected from unanesthetized and freely moving animals. Basal levels obtained at a prelesion stage (day 12 of PTD treatment) were unchanged from levels in pair-fed controls. In samples collected 4-5 h after onset of seizures (day 14 of PTD), the levels of glutamate were elevated an average 640% of basal levels in medial thalamus and 200% in hippocampus. Glutamine levels declined, taurine and glycine were elevated, and aspartate, GABA, and alanine were unchanged during this period. Within 7 h after seizure onset glutamine was undetectable in both areas, whereas glutamate had declined to approximately 200% in thalamus and 70% in hippocampus. No significant change in glutamate, aspartate, or other amino acids was observed in dialysates collected from probes located in undamaged dorsal-lateral regions of thalamus. Number of neurons within ventrolateral nucleus of thalamus was significantly greater in PTD animals in which the probe was dialyzed compared with nondialyzed, suggesting that removal of excitatory amino acids was protective. No significant pathologic damage was evident in hippocampus.(ABSTRACT TRUNCATED AT 250 WORDS)