Concordance between the In Vivo Content of Neurospecific Proteins (BDNF, NSE, VILIP-1, S100B) in the Hippocampus and Blood in Patients with Epilepsy

The identification of reliable brain-specific biomarkers in periphery contributes to better understanding of normal neurophysiology and neuropsychiatric diseases. The neurospecific proteins BDNF, NSE, VILIP-1, and S100B play an important role in the pathogenesis of neuropsychiatric disorders, including epilepsy. This study aimed to assess the correspondence of the expression of BDNF, NSE, VILIP-1, and S100B in the blood (serum and peripheral blood mononuclear cells (PBMCs)) to the in vivo hippocampal levels of subjects with drug-resistant epilepsy who underwent neurosurgery (N = 44) using multiplex solid-phase analysis, ELISA, and immunohistochemical methods, as well as to analyze the correlations and associations of the blood and hippocampal levels of these proteins with clinical parameters. We first studied the concordance between in vivo brain and blood levels of BDNF, NSE, VILIP-1, and S100B in epileptic patients. A positive correlation for NSE between hippocampal and PBMC levels was revealed. NSE levels in PBMCs were also significantly correlated with average seizure duration. BDNF levels in PBMCs were associated with seizure frequency and hippocampal sclerosis. Thus, NSE and BDNF levels in PBMCs may have potential as clinically significant biomarkers. Significant correlations between the levels of the neurospecific proteins studied herein suggest interactions between BDNF, NSE, VILIP-1, and S100B in the pathophysiology of epilepsy.

Brain but not serum BDNF levels are associated with structural alterations in the hippocampal regions in patients with drug-resistant mesial temporal lobe epilepsy

Mesial temporal lobe epilepsy is the most common type of focal epilepsy, imposing a significant burden on the health care system worldwide. Approximately one-third of patients with this disease who do not adequately respond to pharmacotherapy are considered drug-resistant subjects. Despite having some clues of how such epileptic activity and resistance to therapy emerge, coming mainly from preclinical models, we still witness a scarcity of human data. To narrow this gap, in this study, we aimed to estimate the relationship between hippocampal and serum levels of brain-derived neurotrophic factor (BDNF), one of the main and most widely studied neurotrophins, and hippocampal subfield volumes in patients with drug-resistant mesial temporal epilepsy undergoing neurosurgical treatment. We found that hippocampal (but not serum) BDNF levels were negatively correlated with the contralateral volumes of the CA1 and CA4 subfields, presubiculum, subiculum, dentate gyrus, and molecular layer of the hippocampus. Taken together, these findings are generally in accordance with existing data, arguing for a proepileptic nature of BDNF effects in the hippocampus and related brain structures.

Neurospecific Molecules Measured in Periphery in Humans: How Do They Correlate with the Brain Levels? A Systematic Review

Human brain state is usually estimated by brain-specific substances in peripheral tissues, but, for most analytes, a concordance between their content in the brain and periphery is unclear. In this systematic review, we summarized the investigated correlations in humans. PubMed was searched up to June 2022. We included studies measuring the same endogenous neurospecific analytes in the central nervous system and periphery in the same subjects. Not eligible were studies of cerebrospinal fluid, with significant blood–brain barrier disruption, of molecules with well-established blood-periphery concordance or measured in brain tumors. Seventeen studies were eligible. Four studies did not report on correlation and four revealed no significant correlation. Four molecules were examined twice. For BDNF, there was no correlation in both studies. For phenylalanine, glutamine, and glutamate, results were contradictory. Strong correlations were found for free tryptophan (r = 0.97) and translocator protein (r = 0.90). Thus, only for three molecules was there some certainty. BDNF in plasma or serum does not reflect brain content, whereas free tryptophan (in plasma) and translocator protein (in blood cells) can serve as peripheral biomarkers. We expect a breakthrough in the field with advanced in vivo metabolomic analyses, neuroimaging techniques, and blood assays for exosomes of brain origin.

Winter-summer difference in post-awakening salivary α-amylase and sleepiness depending on sleep and melatonin

Winter and summer seasons are contrasted by light/dark conditions at temperate latitudes, and the negative influence of this contrast on circadian health is yet to be quantified. This field study (performed in Novosibirsk, 55°N, no daylight saving time transitions) aimed to compare post-awakening arousal state in summer and winter in subjects (N=45) on a fixed 5-workday schedule (waken up by alarm at either ∼6 am or ∼7 am). Their circadian status (by 24-h melatonin profiles) and sleep (by log data) have been previously reported. Salivary α-amylase levels (a biomarker of the sympathetic nervous system activity, or stress) and subjective sleepiness were measured immediately after awakening on Friday, at minute 0 (supine), 10, 20, and 30 (not supine). α-Amylase levels were found to be higher in winter, along with a blunted α-amylase awakening response (AAR; a decline from minute 0 to minute 10 value). Both effects were attributable mainly to the 7am group. Sleepiness levels also increased in winter, mainly due to the seasonally dependent subjects, and predictably associated with shorter, later sleep, and later melatonin circadian phase. The sleepiness and α-amylase changes did not correlate. The seasonal change in α-amylase was positively associated with the change in the amount of melatonin secreted, probably reflecting the parallelism in the noradrenergic neural control of both α-amylase and melatonin secretion. Together, higher post-awakening salivary α-amylase levels (indicating stress) and subjective sleepiness levels (indicating greater sleep need) in winter compared to summer point to a less healthy state in winter.

Stimulation of macrophages increases, while suppression of these cells inhibits metastatic dissemination of two transplantable mouse tumors in the liver and lungs

Stimulation of mouse tissue macrophages with carboxymethylated beta-(1-->43)-D-glycan 1 day before intravenous injection of tumor cells increased the number and weight of implants (experimental metastases) of mouse hepatocarcinoma and adenocarcinoma in the liver and lungs, respectively. Suppression of liver macrophages with gadolinium chloride or sequestration of cells during intraperitoneal administration of macrophage attractants inhibited metastatic dissemination of hepatocarcinoma and adenocarcinoma in the liver and lungs, respectively. In the latter case animal lifespan increased. Our results indicate that at certain stages of metastatic dissemination, activation of mononuclear phagocytes can stimulate the formation and growth of metastases.

Macrophage Stimulator beta-(1-->3)-D-carboxymethylglucan improves the efficiency of chemotherapy of Lewis lung carcinoma

We studied the effect of macrophage stimulator water-soluble beta-(1-->3)-D-carboxymethylglucan on the efficiency of cyclophosphamide chemotherapy in Lewis lung carcinoma. Cyclophosphamide inhibited the growth of primary tumor nodes by 57%. The preparation possessed pronounced antimetastatic activity: metastases were found in 40.9% animals. Combination therapy with cyclophosphamide and (1-->3)-beta;-D-glucan inhibited the growth of intramuscular tumors by 75-89% and reduced the incidence of metastases into the lungs by 92-94%. The therapeutic effect was most pronounced after simultaneous administration of these preparations: tumor growth was suppressed by 89.3% and metastases were found in only 7.5% animals (vs. 100% in the control). The potentiating effect of beta-(1-->3)-D-carboxymethylglucan is related to accumulation of cysteine proteinase inhibitors in the tumor tissue and plasma, but not to changes in blood cell composition.

Role of cystatin C and cysteine proteinases in the development of mouse LS-lymphosarcoma

The growth of LS-lymphosarcoma in CBA mice was accompanied by a decrease in the content of the major extracellular inhibitor cystatin C in the tumor, plasma and, to a lesser extent, in tissues not involved in tumor process (liver and spleen). Cyclophosphamide in a dose of 50 mg/kg prolonged the life-span of animals and decreased tumor size by 80%. Cathepsin B and L activities in the tumor tissue increased by 3 and 7 times, respectively. Cystatin C content in the tumor tissue, spleen, and plasma also increased. Cystatin C assay in tumor tissue and plasma helps to predict the rate of tumor growth and to evaluate the efficiency of antitumor therapy.

Chitotriosidase as a marker of macrophage stimulation

Serum chitotriosidase activity was determined in different conditions accompanied by macrophage stimulation. Stimulation of macrophages with zymosan, yeast polysaccharide carboxymethylglucan (fraction II), and lysosomotropic preparation Triton WR-1339 1.5-2.0-fold increased enzyme activity. Chitotriosidase activity in intact Wistar rats was similar to that in humans, while in CBA and A/Sn mice this parameter was 5-fold higher. Sharp increase in chitotriosidase activity in the serum from patients with type I Gaucher's disease was probably related to intense secretion of the enzyme by macrophages. Under experimental conditions, stimulation of rat and mouse macrophages (mainly liver cells) caused no increase in chitotriosidase activity typical of patients with Gaucher's disease.