Search

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.

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., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Filimonova, Pashkov, Moysak, Tropynina, Zhanaeva, Shvaikovskaya, Akopyan, Danilenko, Aftanas, Tikhonova and Rzaev.)

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.

The combination of 4-week repeated social defeat stress (RSDS) and Opisthorchis felineus infection was modeled in C57BL/6 mice. Various parameters were compared between three experimental groups of male mice (SS: mice subjected to RSDS, OF: mice infected with O. felineus, and OF + SS: mice subjected to both adverse factors) and behavior-tested and intact (INT) controls. The combination caused liver hypertrophy and increased the blood level of proinflammatory cytokine interleukin 6 and proteolytic activity of cathepsin B in the hippocampus. Meanwhile, hypertrophy of the spleen and of adrenal glands was noticeable. Anxious behavior in the elevated plus-maze test was predominantly due to the infection, with synergistic effects of an interaction of the two adverse factors on multiple parameters in OF + SS mice. Depression-like behavior in the forced swimming test was caused only by RSDS and was equally pronounced in SS mice and OF + SS mice. Helminths attenuated the activities of cathepsin B in the liver and hypothalamus (which were high in SS mice) and increased cathepsin L activity in the liver. The highest blood level of corticosterone was seen in SS mice but was decreased to control levels by the trematode infection. OF mice had the lowest level of corticosterone, comparable to that in INT mice. Thus, the first data were obtained on the ability of O. felineus helminths-even at the immature stage-to modulate the effects of RSDS, thereby affecting functional connections of the host, namely "helminths → liver↔brain axis.", (Copyright © 2022. Published by Elsevier Inc.)

In a parallel placebo-controlled study, we examined the effect of repetitive transcranial magnetic stimulation (rTMS) on serum concentrations of cortisol and dehydroepiandrosteron sulfate (DHEAS), and their relationships with clinical symptoms in men and women with Parkinson's disease. A 20-day course of real rTMS reduced the UPDRS and UPDRS III scores in patients with Parkinson's disease in comparison with the basal parameters (before rTMS), regardless of their sex. The level of cortisol did not change in men and women; at the same time, the content of DHEAS in men increased and before rTMS negatively correlated with the UPDRS scores. Sham rTMS had no effects on clinical parameters or hormonal levels. Possible mechanisms of sex-dependent differences in the effect of rTMS on the level of the neurosteroid hormone DHEAS are discussed., (© 2022. Springer Science+Business Media, LLC, part of Springer Nature.)

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., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Intact Disc1-L100P mice carrying a point mutation DISC1 Rgsc1390 in the second exon of the DISC1 gene (genetic model of schizophrenia) differ from the parental C57BL/6NCrl strain by higher content of CD3 + T cells and reduced number of CD19 + B cells in the peripheral blood and spleen. Analysis of T cell subpopulations revealed an increase in the number of CD3 + CD4 + T helpers in the blood of mutant mice and a decrease in the level of CD3 + CD8 + suppressor/cytotoxic T cells and CD3 + CD4 + CD25 + T-regulatory cells. The distribution pattern of inflammatory (IL-1β, IL-2, IL-6, IL-17, IFNγ, and TNFα) and anti-inflammatory (IL-4, IL-10) cytokines specific for Disc1-L100P mice was revealed in the brain structures involved in the pathogenesis of schizophrenia. A possible implication of immune mechanisms in the development of schizophrenia-like endophenotype of Disc1-L100P mice is discussed., (© 2021. Springer Science+Business Media, LLC, part of Springer Nature.)

We analyzed the behavior and peripheral blood T- and B-cell subpopulations in mice overexpressing the mutant form of human α-synuclein (A53T) in comparison with mice of the wild type (WT) parent C57BL/6J strain. Behavioral phenotype and the content of various cell subpopulations of A53T mice depended on animal age. Young (2-month-old mice) were characterized by low emotionality and the most pronounced changes in cell subpopulation composition (an increase in CD3 + T cells and CD4 + T helper cells, a decrease in CD19 + B cells along with unchanged content of CD3 + CD4 + CD25 + T-regulatory cells and CD19 + CD25 + B-regulatory cells). In old A53T mice (10-month-old), movement impairments appeared and increased numbers of CD4 + T helper cells and CD3 + CD4 + CD25 + T-regulatory cells were revealed.

The DISC1 (disrupted in sсhizophrenia 1) gene is associated with brain dysfunctions, which are involved in a variety of mental disorders, such as schizophrenia, depression and bipolar disorder. This is the first study to examine the immune parameters in Disc1-Q31L mice with a point mutation in the second exon of the DISC1 gene compared to mice of the C57BL/6NCrl strain (WT, wild type). A flow cytometry assay has shown that intact Disc1- Q31L mice differ from the WT strain by an increase in the percentage of CD3+ T cells, CD3+CD4+ Т helper cells and CD3+CD4+CD25+ T regulatory cells and a decrease in CD3+CD8+ T cytotoxic/suppressor cells in the peripheral blood. A multiplex analysis revealed differences in the content of cytokines in the brain structures of Disc1-Q31L mice compared to WT mice. The content of pro-inflammatory cytokines was increased in the frontal cortex (IL-6, IL- 17 and IFNγ) and striatum (IFNγ), and decreased in the hippocampus and hypothalamus. At the same time, the levels of IL-1β were decreased in all structures being examined. In addition, the content of anti-inflammatory cytokines IL-4 was increased in the frontal cortex, while IL-10 amount was decreased in the hippocampus. Immune response to sheep red blood cells analyzed by the number of antibody-forming cells in the spleen was higher in Disc1-Q31L mice at the peak of the reaction than in WT mice. Thus, Disc1-Q31L mice are characterized by changes in the pattern of cytokines in the brain structures, an amplification of the peripheral T-cell link with an increase in the content of the subpopulations of CD3+CD4+ T helpers and CD3+CD4+CD25+ T regulatory cells, as well as elevated immune reactivity to antigen in the spleen., (Copyright © AUTHORS.)

The content of pro- and anti-inflammatory cytokines in the hypothalamus, hippocampus, and blood serum of C57Bl/6J mice with depressive-like behavior induced by 20-day social stress was analyzed in 4 h after immune stimulation with LPS (250 μg/kg). These animals are characterized by a tendency to an increase in the blood content of IL-6 and a decrease in the level of IL-10. Changes in cytokine content in the brain of mice with depressive-like state developed under these conditions were observed only in the hippocampus: the levels of IL-1β, IL-6, TNFα, and IL-10 increased and the content of IFNγ decreased in comparison the corresponding parameters in the controls (not exposed to social stress) and aggressive animals. No changes in the levels of IL-2, IL-4, and IL-17 were revealed in the hypothalamus and hippocampus.

The parallel placebo-controlled study examined the therapeutic effects of dual-target repetitive transcranial magnetic stimulation (rTMS) of the motor cortex (bilaterally) and the left prefrontal cortex (dorsolaterally) on spontaneous and mitogen-stimulating synthesis of pro- and anti-inflammatory cytokines by the blood cells and the level of brain-derived neurotrophic factor (BDNF) in blood serum of patients with Parkinson's disease. The significantly steeper positive clinical dynamics (assessed by UPRSD scale) observed in rTMS group in comparison with the placebo group was accompanied by a significant drop in spontaneous production of proinflammatory cytokines IFNγ and IL-17A. rTMS produced no significant effect on serum BDNF. The possible mechanisms of rTMS therapeutic action on the level of cytokines associated with neuroinflammation in patients with Parkinson's disease are discussed.

We studied the influence of depression-like behavior developed in C57BL/6J mice under conditions of social stress of different duration on cytokine production by splenic cells. Imbalance of the pro- and anti-inflammatory cytokines was detected at the early stage of depression-like behavior (10-day experience of defeats): increased production of proinflammatory IL-2 and IL-6 cytokines along with a decrease in anti-inflammatory IL-10 level; the levels of IL-1β, TNFα, IFNγ, and IL-4 remained unaffected. At later terms (20 days of confrontations), we revealed more pronounced changes in spontaneous production of proinflammatory cytokines that were not detected after shorter social stress. These findings suggest that cytokine profile depends on duration of social stress. Possible mechanisms of cytokine production during formation of depression-like state are discussed.

We studied activity of lysosomal cysteine proteases, cathepsins B and L, in brain structures (frontal cortex, caudate nucleus, hippocampus, and hypothalamus) of C57Bl/6J mice with aggressive and depressive-like behavior formed under conditions of chronic social stress (repeated experience of victories and defeats within 20 days). Mice with depressive-like behavior showed increased activity of cathepsin В in the hypothalamus and nucleus caudatus and increased activity of cathepsin L in the hippocampus compared to control animals not subjected to agonistic confrontations. In mice with aggressive behavior, protease activity in the studied brain structures was not changed. In 4 h after immune system activation with LPS (250 μg/kg), cathepsin L activity in the hippocampus of control mice increased in comparison with mice receiving saline. In contrast to control animals, LPS caused a decrease in activity of the enzyme in the caudate nucleus and frontal cortex of aggressive mice and in the hippocampus of mice with depressive-like behavior.

The effects of two influences, social stress and acute opisthorchiasis, were investigated in inbred C57BL/6J male mice. In the model of social stress, mice were repeatedly attacked and defeated by aggressive outbred ICR male mice and were in continuous sensory contact with an aggressive conspecific mouse in their home cage for 20 days. Acute opisthorchiasis was provoked by invasion of Opisthorchis felineus (50 larvae per animal) on the fourth day after the social stress was induced. Simultaneous action of both factors caused the hypertrophy of adrenal glands, as well as elevated the activity of cathepsins B and L in the spleen. This effect on the activity of the cysteine proteases in the hippocampus and hypothalamus following O. felineus invasion was the predominant result of simultaneous action with social stress. Acute opisthorchiasis, social stress, and their combination caused an increase in the level of blood IL-6 in approximately 30% of the animals. Social stress induced a more pronounced effect on mouse plus-maze behavior than O. felineus invasion. Our results suggest a more severe negative effect of the simultaneous influence of both factors on most of the parameters that were investigated., (Copyright © 2016 Elsevier Inc. All rights reserved.)

We analyzed activities of lysosomal cystein cathepsins B and L in mouse LS lymphosarcoma and its drug-resistant RLS 40 strain and their correlations with the dynamics of the percentage of cells with fragmented DNA and CD14 (+) phagocytes over 3 days after cyclophosphamide injection. LS regression and inhibition of RLS 40 growth after cyclophosphamide injection were paralleled by an increase in cathepsins B and L activities in tumor tissues. The antitumor effect of cyclophosphamide associated with apoptosis intensity and protease activities were significantly higher in LS. Positive correlations between activities of cathepsins B and L and the LS tissue content of cells with fragmented DNA and CD14 (+) phagocytes and negative correlations thereof with tumor weight were detected. It seems that the increase in cathepsins B and L activities in LS tissues was caused by cyclophosphamide induction of apoptosis and depended on the level of tumor cell infiltration with mononuclear phagocytes.

Chronic administration of the poloxamer 407 (P-407), a block copolymer, to elevate serum lipids in mice is a well-established mouse model of hyperlipidemia and atherosclerosis. We tested the hypothesis that the activity of several types of proteases in heart and liver tissue is changed in the early stages of atherosclerosis development. Additionally, we evaluated whether increased serum lipids would induce anxiety in mice, as determined by using a 'plus-maze' test. The mice were administered P-407 by intraperitoneal injection twice a week for one month. P-407 administration to mice resulted in a marked increase in total serum cholesterol, atherogenic non-HDL-cholesterol, and especially in total triglycerides, and it also increased anxiety. Morphological changes observed in P-407-treated mice included contractile type changes in cardiomyocytes and foamy macrophages in liver. A significant increase of cysteine proteases cathepsin B and cathepsin L (at 24 h) and aspartate protease cathepsin D (at both 24 h and 5 days) was determined in heart tissue following P-407 administration. However, no changes were noted in heart matrix metalloproteinase activity. The activity of cysteine and aspartate proteases was significantly increased in liver at both 24 hours and 5 days after P-407 administration. In conclusion, administration of P-407 to mice for one month resulted in increased anxiety, and more importantly, there was an increase in the activity of heart and liver proteases secondary to sustained dyslipidemia. It is suggested that heart and liver cysteine and aspartate proteases may represent potential therapeutic targets in the early stages of atherosclerosis.

The effects of repeated administration of poloxamer 407 (P-407) on lipoprotein-cholesterol (LP-C) and lipoprotein-triglyceride (LP-TG) fractions and subfractions, as well as the effect on liver and heart proteases, were studied. Repeated administration of P-407 to male CBA mice resulted in a model of atherosclerosis with increased diastolic blood pressure; there was a drastic increase in total serum cholesterol and especially TG. A novel small-angle X-ray scattering method for the determination of the fractional and subfractional composition of LP-C and LP-TG was used. In chronically P-407-treated mice, P-407 significantly increased atherogenic low-density lipoprotein C (LDL-C) fractions, as well as intermediate-density lipoprotein C (IDL-C), and LDL₁₋₃-C subfractions, and very-low-density lipoprotein-C (VLDL-C) fractions, as well as VLDL₁₋₂-C and VLDL₃₋₅-C subfractions), to a lesser extent, the total anti-atherogenic high-density lipoprotein C (HDL-C) fraction, as well as HDL₂-C and HDL₃-C subfractions. Additionally, we demonstrated an increase in the serum chitotriosidase activity, without significant changes in serum matrix metalloprotease (MMP) activity. Morphological changes observed in P-407-treated mice included atherosclerosis in the heart and storage syndrome in the liver macrophages. P-407 significantly increased the activity of cysteine, aspartate proteases, and MMPs in the heart, and only the activity of cathepsin B and MMPs in the liver of mice. Thus, repeated administration of P-407 to mice induced atherosclerosis secondary to sustained dyslipidemia and formation of foamy macrophages in liver, and also modulated the activity of heart and liver proteases.

Tissue inhibitor of matrix metalloproteinases type 1, inhibiting the majority of matrix metalloproteinases, can both suppress and stimulate tumor growth. The concentrations and activities of tissue matrix metalloproteinase inhibitor-1 were measured in C57Bl/6 mice during progression and metastasizing of Lewis lung adenocarcinoma. Activities of matrix metalloproteinases in tumor tissue of mice were lower than in liver and lung tissues of intact animals. Serum concentration of tissue inhibitor increased significantly during the development of Lewis lung adenocarcinoma. Macrophage depression (injection of gadolinium chloride associated with a decrease in metastasis number) decreased serum concentration of tissue inhibitor, but it did not attain the control level observed in intact mice. These findings attest to a pleiotropic antitumor effect of tissue matrix metalloproteinase inhibitor-1 reflecting disorders in matrix metalloproteinase regulation during the progress of Lewis lung adenocarcinoma in mice.

By means of carboxymethylation, a novel water-soluble carboxymethyl chitin-glucan (CM-CG) was prepared from the mycelium of Aspergillus niger, and its ability to stimulate macrophages was assessed and compared to that of the previously studied carboxymethylated glucan (CMG) from the yeast Saccharomyces cerevisiae. It was demonstrated that single intraperitoneal (i.p.) administration of CMG and CM-CG to the CBA mice led to a significant increase of leukocyte number. At the same time, the number of monocytes in the bone marrow was increased to more than two-fold. Application of both polysaccharides also resulted in the augmented number of liver macrophages and to the rise of their content of the secondary lysosomes. A markedly enhanced carbon clearance was observed as well as the increased release of tumor necrosis factor-alpha by the peritoneal macrophages indicating their amplified phagocytic activity. The effect of CM-CG in these experiments was ca. 1.7 times higher than that of CMG. Administration of both polysaccharides also led to the elevated level of free acid phosphatase in liver homogenate, implying labilization of the lysosomes. Increased serum chitotriosidase also indicated increased macrophage activity. The results obtained indicate similar in vivo macrophage stimulation activity of both applied fungal polysaccharides and suggest their potential clinical use as non-toxic natural compounds.

A single intraperitoneal injection of GdCl(3)in doses of 14 or 28 mg/kg to mice with intravenously transplanted Lewis pulmonary adenocarcinoma on days 3 or 8 after tumor transplantation reduced the mean number of tumor metastases in the lungs. The effect of GdCl(3)was more pronounced if it was injected at the stage of tumor dissemination (day 8). The positive antimetastatic effect of GdCl(3)was presumably due to its capacity to macrophage depression. The direct (not mediated through mononuclear phagocyte system cells) effect of GdCl(3)on tumor cells cannot also be excluded.

We studied the role of selective suppression of liver Kupffer cells (gadolinium chloride, 14 mg/kg intravenously) in the development of intrahepatic cholestasis in CBA/C57B1/6 mice after intraperitoneal injection of alpha-naphthylisothiocyanate in a single dose of 200 mg/kg. Pretreatment with gadolinium chloride increased the severity of cholestasis and signs of liver damage. Gadolinium accumulation in the liver peaked after 24 h and was accompanied by a decrease in activities of cathepsin D and cathepsin B and concentration of matrix metalloprotease-2. Our results confirm the hypothesis that normal function of Kupffer cells and extracellular matrix plays an important role in cholestasis. Administration of gadolinium chloride serves as a convenient model to study the side effects, toxicity, and safety of lanthanides as nanoparticles.

Aim: One of the advanced methodologies of the tumor therapy is the application of the so-called biological response modifiers used for activation of the endogenous antitumor mechanisms and combined with classical cytotoxic agents. The aim of this work was the investigation of the effect of sulfoethylated (1-->3)-beta-D-glucan (SEG) in the treatment of experimental murine leukoses in combination with cyclophosphamide (CPA) and its ability to modulate the activity of lysosomal enzymes in tumor tissues., Materials and Methods: The solid forms of inoculated murine leukoses P388 and L1210/1 were transplantated to male DBA/2 mice. The therapy was performed by treating animals with CPA (Biokhimik, Saransk, Russia) alone or in combination with SEG (Institute of Chemistry, Slovak Academy of Sciences, Slovakia). CPA was administered in saline as a single intraperitoneal (ip) injection on the 10th day after tumor transplantation; SEG was administered to mice ip 3 days after tumor transplantation with the intervals in 3 days. The therapy effect was estimated by measuring of solid tumor volume. Activity of the cysteine proteases--cathepsins B and L--was measured fluorometrically using fluorescent substrates Z-Arg-Arg-MCA and Z-Phe-Arg-MCA (Sigma, USA), respectively. The apoptosis was estimated evaluating the number of cells with fragmented nuclei using optical microscope., Results: It has been demonstrated that application SEG leads to inhibition of tumor growth and potentiates therapeutic action of CPA, especially at repeated administrations during the whole treatment/observation At addition of SEG, therapeutic effect of a one-half reduced dose of CPA is equal or higher than that of the full dose. Therapeutic action of CPA and SEG on the studied tumors is realized predominantly through induction of apoptosis and is accompanied by a substantial increase of the activity of cysteine proteases cathepsins B and L in tumor tissues. The highest cathepsin B and cathepsin L activity in tumor tissue accompanied with the strongest inhibition of tumor growth. It is suggested that this phenomenon is due to the infiltration of the macrophages rich in the named enzymes into the tumor, where they phagocytize the apoptotic cells and tissue debris., Conclusion: Utilization of this polysaccharide BRM, sulfoethylated (1-->3)-beta-D-glucan, might potentially enhance efficiency of antitumor therapy with standard cytostatics without a need of substantial increase of their dosage and hence avoiding their toxic side-effects.

Kinetics of gadolinium accumulation was studied by inductively coupled plasma-emission spectroscopy after intravenous injection of this agent (7.5 mg/kg) to CBA mice. Gadolinium exhibits lysosomotropic properties (long-term selective accumulation in lysosomes in vivo). Gadolinium uptake by hepatic cells attained maximum 1 h after its intravenous injection and remained at this level during the next day. Accumulation of gadolinium in hepatocytic lysosomes disturbed their osmotic properties (as was seen from the increase in free acid phosphatase activity, which persisted for 19 days). Serum activities of beta-D-galactosidase and beta-D-glucuronidase also increased (24-72 h and day 19). Selective depression of liver macrophages (24-48 h) was accompanied by a decrease in serum chitotriosidase activity. We conclude that accumulation of gadolinium in lysosomes of liver macrophages leads to their damage and elimination of a certain population of macrophages (primarily large cells). Changes in activity of serum lysosomal enzymes also reflect repopulation of liver macrophages.

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.

Changes in the activity of cysteine (cathepsins B and L) and aspartyl (cathepsin D) proteases were investigated at the development of susceptible and resistant variants of murine lymphosarcoma (LS). It has been demonstrated that the variant resistant to the cyclophosphamide treatment is characterized by a lower activity of all three cathepsins in the tumor tissue. Application of a higher dose of cyclophosphamide led to a more pronounced increase of the studied enzymatic activity in mice with a resistant variant of LS, than in those with a susceptible one. Administration of a yeast polysaccharide derivative - sulfoethyl glucan - enhanced therapeutic effect of cyclophosphamide in mice with both variants of LS, while the most efficient dose was found to be that of 10mg/kg body mass. In the intact mice, usage of both cyclophosphamide and sulfoethyl glucan led to a similar increase of the cathepsins activity in liver and spleen.

Cyclophosphamide 1.5-2.0-fold increased activity of cathepsins B and L in tumor tissue of mouse lymphosarcoma LS and caused tumor regression. The effect was most pronounced on day 5 after treatment. Twofold treatment with a selective cathepsin inhibitor Ep-475 slightly stimulated tumor growth in control mice and significantly reduced the antitumor effect of cyclophosphamide. Lysosomal cysteine proteases cathepsins B and L are involved, but do not play a key role in TNF-alpha-independent apoptosis in LS cells induced by cyclophosphamide.

Gadolinium chloride (5 mg/kg) administered to mice 24 h before intravenous transplantation of HA-1 hepatoma cells decreased the volume density of tumor implants in the liver, reduced the intensity of degenerative and necrotic changes developing under the effect of growing tumor metastases, and prolonged the life span of tumor-bearing mice. Development of metastases was not associated with changes in cathepsin B activity in the liver, while activity of cathepsin L decreased only during the early period (4 days) after injection of gadolinium chloride. Injection of gadolinium chloride led to labilization of liver cell lysosomes because of overload with gadolinium chloride particles. The positive effect of gadolinium chloride was probably associated with depression of liver macrophages at the stage of tumor cell invasion and with subsequent migration of monocytes/macrophages preventing the growth of formed metastatic nodes in the liver.

We measured activities of cysteine (cathepsins B and L) and aspartyl proteinases (cathepsin D) in tumor tissue of mice with sensitive and resistant lymphosarcomas. In cyclophosphamide-resistant lymphosarcoma tissue activities of cathepsins B, L, and D were lower than in cyclophosphamide-sensitive lymphosarcoma. After treatment with cyclophosphamide in high doses enzyme activities in mice with cyclophosphamide-resistant lymphosarcoma increased more significantly than in animals with cyclophosphamide-sensitive lymphosarcoma. Sulfoethylated beta-1,3-D-glycan potentiated the effect of cyclophosphamide in mice with both forms of lymphosarcoma. This drug in the lowest dose (10 mg/kg) was most effective.

The efficiency of chemotherapy of Lewis lung carcinoma with cyclophosphamide was affected by administration of the water-soluble yeast polysaccharide derivative--carboxymethylated (1 --> 3)-beta-D-glucan (CMG)-a well-known macrophage stimulator. It was found that while cyclophosphamide showed 57% growth inhibition of the intramuscular tumor implants in comparison with the control group, its combined administration with CMG led to 75-90% inhibition. Similarly, increased inhibition of occurrence of lung metastases (up to 92-94%) was observed using the combined application of the two compounds. The stimulatory effect of CMG is not associated with the changed cellularity of peripheral blood, but is rather due to the obviously increased concentration of the intracellular inhibitor of cysteine proteases-stefin A and cystatin C in tumor tissue.

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.

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.