The human body as an energetic hybrid? New perspectives for chronic disease treatment?

Inflammatory response is accompanied by changes in cellular energy metabolism. Proinflammatory mediators like plasma C-reactive protein, IL-6, plasminogen activator inhibitor-1, TNF-α or monocyte chemoattractant protein-1 released in the site of inflammation activates immune cells and increase energy consumption. Increased demand for energy creates local hypoxia and lead in consequence to mitochondrial dysfunction. Metabolism of cells is switched to anaerobic glycolysis. Mitochondria continuously generate free radicals that what result in imbalance that causes oxidative stress, which results in oxidative damage. Chronic energy imbalance promotes oxidative stress, aging, and neurodegeneration and is associated with numerous disorders like Alzheimer's disease, multiple sclerosis, Parkinson's disease or Huntington's disease. It is also believed that oxidative stress and the formation of free radicals play an important role in the pathogenesis of rheumatoid diseases including especially rheumatoid arthritis. Pharmacological control of energy metabolism disturbances may be valuable therapeutic strategy of treatment of this disorders. In recent review we sum up knowledge related to energy disturbances and discuss phenomena such as zombies or hibernation which may indicate the potential targets for regulation of energy metabolism.

Esculetin reduces leukotriene B4 level in plasma of rats with adjuvant-induced arthritis.

OBJECTIVES: Esculetin (6,7-dihydroxycoumarin) is a natural coumarin with anti-oxidant, anti-inflammatory and anti-nociceptive activity. It acts as a potent inhibitor of lipoxygenases (5-LOX and 12-LOX) and decreases the production of matrix metalloproteinases (MMP-1, MMP-3 and MMP-9). Because both inhibition of lipoxygenases and inhibition of matrix metalloproteinases are effective strategies in the treatment of rheumatoid arthritis, we investigated whether esculetin may be effective in adjuvant-induced arthritis in rats. MATERIAL AND METHODS: The study was performed on male Lewis rats, in the adjuvant-induced arthritis model. Rats were divided into two groups: control (treated with 1% methylcellulose) and experimental (treated with esculetin - 10 mg/kg ip.). The tested compound was administered for 5 consecutive days starting on the 21st day after induction of arthritis. Each group consisted of 7 animals. After 5 days of treatment, rats were anesthetized. The concentration of leukotriene B4 (LTB4) in plasma was determined by a competitive enzyme immunoassay. RESULTS: The LTB4 level in plasma of rats with adjuvant-induced arthritis is increased in comparison to rats without inflammation (362 ±34 vs. 274 ±15 pg/ml, p < 0.01, respectively). Five-day treatment with esculetin in adjuvant-induced arthritis rats decreases the LTB4 level to a level comparable with rats without inflammation (284 ±23 pg/ml, p < 0.01). CONCLUSIONS: LTB4 is the most potent chemotactic agent influencing neutrophil migration into the joint. It is known that its level in serum of patients with active rheumatoid arthritis is increased and correlates with disease severity. Some other lipoxygenase inhibitors have already been tested as potential drug candidates in clinical and preclinical trials for rheumatoid arthritis (Zileuton, PF-4191834). Because esculetin decreases the LTB4 level in plasma of rats in adjuvant-induced arthritis, it may also be considered as an attractive drug candidate for patients with rheumatoid arthritis.

Antinociceptive properties of esculetin in non-inflammatory and inflammatory models of pain in rats.

Some studies suggest that 5-lipoxygenase (5-LOX) inhibition or leukotriene receptor antagonism may effectively attenuate different kinds of pain. In the present study, we investigated whether esculetin (which, among other actions, potently inhibits 5-LOX) possesses analgesic activity in acute non-inflammatory pain and acute inflammatory pain models in rats. We also examined the effects of zileuton, a selective 5-LOX inhibitor, on esculetin activity. Plasma concentrations of leukotriene B4 (LTB4 ) after administration of esculetin were also determined. Esculetin (1.25-20 mg/kg, i.p.) dose-dependently alleviated hyperalgesia and exhibited antinociceptive effects in both experimental models. The greatest effect of esculetin was observed with a dose of 20 mg/kg. In carrageenan-induced inflammatory pain in rats, 20 mg/kg esculetin reversed or mitigated hyperalgesia, increasing the threshold to mechanical stimuli from a control value of -23.8 ± 1.8% to 15.2 ± 2.2% (P < 0.01) and that to thermal stimuli from -52.5 ± 6.1% to -9.5 ± 3.9% (P < 0.01). In non-inflammatory pain, after esculetin (20 mg/kg) administration the threshold values to mechanical and thermal stimuli increased to 75.9 ± 4.2% and 59.2 ± 4.3%, respectively (P < 0.01 for both). Zileuton (30 mg/kg, p.o.) alone slightly but significantly increased the pain threshold in the non-inflammatory and inflammatory acute pain models. Pretreatment with 30 mg/kg, p.o., zileuton significantly enhanced the analgesic activity of 5 mg/kg, i.p., esculetin in both pain models. Moreover, esculetin (10 mg/kg, i.p.) decreased LTB4 concentrations in the blood from 244 ± 29 pg/mL in the control group to 185 ± 11 pg/mL (P < 0.005). The results of the present study suggest the involvement of the 5-LOX pathway in esculetin analgesia.

The role of physiological elements in future therapies of rheumatoid arthritis. III. The role of the electromagnetic field in regulation of redox potential and life cycle of inflammatory cells.

Each material consisting of charged particles can be influenced by a magnetic field. Polarized particles play an essential role in almost all physiological processes. Locally generated electromagnetic fields several physiological processes within the human body, for example: stimulation of nerves, muscles, and cardiac electrical activity. This phenomenon is used today in many medical applications. In this article, we discuss ways in which electromagnetic field affects the physiological and pathological processes in cells and tissues. This knowledge will help to better understand the electrophysiological phenomenon in connective tissue diseases and can bring new therapeutic strategies (in the form of "invisible drugs") for the treatment of rheumatic diseases?

Commitment of protein p53 and amyloid-beta peptide (Aß) in aging of human cerebellum.

Protein p53 is known to induce the cell cycle arrest and apoptosis in response to a variety of cellular distress signals and DNA damage. A recent study has demonstrated that in blood cells of aging subjects, p53 may induce early pathological changes that precede the amyloidogenic cascade. However, it is not clear whether p53 participates in the local deposition of amyloid-beta peptide (Aß) in the nerve tissue of normal aging subjects. Therefore, in the present study, we analyse the distribution of both (Aß and p53) proteins in the cerebellum of individuals without any history of dementia or other neurological illness who died suddenly in traffic accidents. We found that in the subjects at the beginning of their aging process (60-65 years of age) Aß deposits were localized in subependymal areas of the cerebellar cortex and such deposits were not linked to the presence of p53 in the nerve tissue. In groups of subjects over 65 years of age, numerous Aß diffuse plaques were scattered throughout the cerebellar cortex. In these subjects, p53 protein was detected in the cytoplasm or in the nucleus of the cerebellar nerve cells. All the results lead to the conclusion that in nerve tissue p53 participates in the process of neurodegeneration and then it is involved in the deposition of A in the nerve tissue.

Toll-like receptor 2 (TLR2) is a marker of angiogenesis in the necrotic area of human medulloblastoma.

Angiogenesis plays a key role in the progression of malignant tumors. In recent years, anti-angiogenic drugs have been shown to be effective against tumors. However, some tumors are able to adopt escape mechanisms, suggesting that the vascular network in these tumors may be formed or may function in a different way. Medulloblastomas are tumors characterized by poor prognosis and low patient survival rates. These tumors rarely metastasize, but the reason why they almost always recur locally is not known. Central to mediating neoplastic changes is the interaction between cell surface receptors and their cognate ligands, which through intracellular signaling induce alternations in gene expression. In this context, the aim of our present study was to examine in medulloblastoma the distribution of Toll-like receptor 2 (TLR2) and receptor for advanced glycosylation end-product (RAGE), and mast cells associated with the tumor neovascularization process. Immunohistochemical study with a battery of specific antibodies was used. The results show that in the tumor necrotic area, TLR2 participates in all steps of vascular network formation, but in regions where the tumor was not affected by necrosis, the capillary network was TLR2 immunonegative. The TLR2 vascular network of the necrotic area was not associated with RAGE and mast cells. However, in the region of the medulloblastoma not affected by necrosis, the RAGE receptor was present in the endothelium of all capillaries, and mast cells were numerous only in the perivascular space of large brain and meningeal vessels at the border of the tumor. In conclusion, our results show that the receptor of innate immunity TLR2 plays an important role in recognition of ligands delivered by dying necrotic medulloblastoma cells and participates in tumor neovascularization. Moreover, the results show that the RAGE receptor and mast cells operate in different medulloblastoma regions and influence different parts of the tumor vascular network.

Genetic polymorphisms of Foxp3 in patients with rheumatoid arthritis.

OBJECTIVE: The aim of the study was to identify 2 polymorphic variants in the promoter region of the Foxp3 gene and their possible association with susceptibility to and severity of rheumatoid arthritis (RA). The association between genetic factors and pathogenesis suggests that T cells take part in the induction of RA. The CD4+CD25highFoxp3+ subset of regulatory T cells plays an essential role in preventing autoimmunity and maintaining immune homeostasis. METHODS: Patients with RA (n = 274) and healthy individuals (n = 295) were examined for -3279 C/A and -924 A/G Foxp3 gene polymorphisms by the polymerase chain reaction-restriction fragment-length polymorphism method. Serum Foxp3 levels in patients with RA and controls were measured with ELISA. RESULTS: Foxp3 -3279 A and -924 G alleles were associated with significantly elevated risk of RA in the population tested (p = 0.003 and p = 0.004, respectively) compared to the wild-type alleles. Overall, -3279 C/A and -924 A/G Foxp3 gene polymorphisms were in indistinct linkage disequilibrium with D' = 0.481 and r(2) = 0.225. From 4 possible haplotypes, frequencies of 2 (AG and CA) showed significant differences between both examined groups (respectively, p < 0.001 and p = 0.007). After appropriate adjustment of Bonferroni correction for multiple testing, the genotype-phenotype analysis showed no significant correlation of the Foxp3 -3279 C/A and -924 A/G polymorphisms with the disease activity, joint damage, laboratory variables, and extraarticular manifestation in patients with RA. Serum Foxp3 level was significantly higher in patients than in controls (p < 0.0001). CONCLUSION: Current findings indicated that the Foxp3 genetic polymorphism and the Foxp3 protein level may be associated with susceptibility to RA in the Polish population.

Toll-like receptors in rat brains injured by hypoxic-ischaemia or exposed to staphylococcal alpha-toxin.

Some data suggest that the central nervous system (CNS) is the main target of Staphylococcus alpha-toxin. Since this pathogen cannot penetrate the blood-brain barrier (BBB), the exact mechanism by which alpha-toxin affects the CNS remains unclear. Recent studies on the role of the innate immune system have shed light on how bacterial infections initiate inflammatory responses within the CNS. The aim of this study was to investigate the immunoexpression of Toll-like receptors (TLR 2, TLR 4) in brains of young rats systemically exposed to Staphylococcus alpha-toxin or injured by neonatal hypoxia-ischaemia. The study was carried out on 6-week-old Wistar rats. A group of 6-week-old rats with severe brain injury caused by neonatal hypoxia-ischaemia was also studied separately. In all control rats, the immunoexpression of TLR 2 and TLR 4 was not detected. However, the expression of both TLRs was evident in all brains injured by HI or exposed to alpha-toxin. The immunoexpression was localised in the wall of the small brain vessels, cells of ependyma and leptomeninges. In such vessels the spectrum of ultrastructural lesions was found. The presence of TLR4 detected in the nerve cells of the subcortical gray matter of the brain is particularly of interest, but requires further studies. The presence of TLR 4 antigen in the nerve cells of the subcortical gray matter is particularly of interest. In conclusion, the results show that brain microvessels through TLRs may participate in the immune response of brain affected by bacterial infection as well as injured by non-infection insults.

Methyl-CpG binding protein 2, receptors of innate immunity and receptor for advanced glycation end-products in human viral meningoencephalitis.

Inflammation is a normal host defense reaction to infections and tissue injury. In pathology, the process of inflammation is deregulated by various environmental factors, prolonged activation of Toll-like receptors (TLRs), induction of epigenetic machinery or expression of receptors for advanced glycation end-products (RAGE). In the present study, we examined immunoexpression of proteins participating in the above-mentioned mechanisms, in the brain of patients with viral meningoencephalitis. The results showed that depending on the period of the disease, the process of inflammation is deregulated in different ways. In an early period of viral meningoencephalitis, we found numerous so-called microglial nodules which were strongly immunopositive to methyl-CpG protein 2 (MeCP2). This protein is an epigenetic factor important for methylation of DNA; therefore, our results suggest that cells collected in the nodules may participate in modification of the host defense reaction. Moreover, in the early period of viral meningoencephalitis, we found that Purkinje cells of the cerebellum contain TLR3 or TLR9 receptors that can recognize viral pathogens and may activate a self-destructive mechanism in these neurons. In the later (advanced) period of viral meningoencephalitis, despite some of the above observations, RAGE protein was detected in the brain of adult and aging patients. It means that in this period of the disease, the inflammatory process may be deregulated by numerous post-translationally modified proteins that are transported to the brain after binding with activated RAGE. In addition, young patients appeared more susceptible to viral infections than adult and aging patients, because most of them died during the early period of meningoencephalitis.

Crosstalk in human brain between globoid cell leucodystrophy and zinc-α-2-glycoprotein (ZAG), a biomarker of lipid catabolism.

Zinc-alpha-2-glycoprotein (ZAG) is a protein identified as a lipid-mobilizing factor participating in a lipid catabolism. In spite of intensive studies conducted during last five decades, the role of this protein in processes of neurodegeneration remains unclear. The aim of our study was to examine the presence of ZAG protein in the brain of patients with Krabbe's disease, which is considered as a psychosine lipidosis caused by a mutation of a known gene. We found intracellular and extracellular localization of ZAG in the brain of Krabbe's disease patients but in the brain of control age-matched patients, ZAG was not detected. Distribution of ZAG in the brain suggests that the influx of ZAG into the brain involved a blood-brain barrier mechanism and adenoreceptors localized on astrocytes and some neurons.

Immunodistribution of amyloid beta protein (Aß) and advanced glycation end-product receptors (RAGE) in choroid plexus and ependyma of resuscitated patients.

RAGE (receptor for advanced glycation end-products) participates in the influx transport of glycated Aß (amyloid beta) from the blood to the brain. Because little is known of the RAGE operating in brain barriers such as those in the choroid plexus and ependyma, the aim of the present study was to examine the immunodistributions of RAGE and Aß peptides in the choroid plexus where the blood-cerebrospinal fluid barrier (B-CSF) is located, and in ependyma of the brain ventricles associated with functions of the cerebrospinal fluid-brain barrier (CSF-B). The study was performed on patients over 65 years successfully resuscitated after cardiac arrest with survival a few weeks. The control group consisted of age-matched individuals who were not resuscitated and died immediately after cardiac arrest. In resuscitated patients, but not in controls, RAGE receptors were localized in choroid plexus (CP) epithelial cells and in ependymal cells bordering the brain ventricles. These cells form the B-CSF and CSF-B barriers. The presence of Aß was detected within the CP blood vessels and in the basement membrane of the CP epithelium. In numerous cytoplasmic vacuoles of CP epithelial and ependymal cells Aß protein was found and our observations suggest that the contents of those vacuoles were undergoing progressive digestion. The results demonstrated that CP epithelium and ependymal cells, equipped with RAGE receptors, not only play an important role in the creation of amyloid deposits in the brain but are also places where Aß may be utilized. The RAGE transportation system should be a main target in the therapy of brain amyloidosis, a well-known risk factor of Alzheimer disease.

Association of mast cells with calcification in the human pineal gland.

Increased pineal calcifications and decreased pineal melatonin biosynthesis, both age related, support the notion of a pineal bio-organic timing mechanism. The role of calcification in the pathogenesis of pineal gland dysfunction remains unknown but the available data document that calcification is an organized, regulated process, rather than a passive aging phenomenon. The cellular biology and micro-environmental conditions required for calcification remain poorly understood but most studies have demonstrated evidence that mast cells are strongly implicated in this process. The aim of the present study was to examine the phenotype of mast cells associated with early stages and with the progressive development of calcification in the human pineal gland. The study was performed on pineal samples of 170 fetuses and children whose brains were autopsied and diagnosed during 1998-2002. The representative cerebral and pineal specimens were stained with haematoxylin and eosin or the von Kossa staining technique and for the distribution of mast cell tryptase, mast cell chymase, histamine H4 receptor and vascular network using biotinylated Ulex europaeus agglutinin. Tryptase mast cells were found in all stages of pineal gland development independently of the presence of local tissue lesions. All of them were always localized in the close vicinity of the blood vessels and expressed immunoreactivity to histamine H4 receptor antibody. Immunolocalization of mast cells by chymase antibody (and following dual immunostaining with both chymase and tryptase antibodies) demonstrated that these cells were few in number and were located in the subcapsular region of the gland. In our study, all functional mast cells that underwent activation and were co-localized with deposits of calcium did not contain chymase. All of them were stained with tryptase and represent the MC-T phenotype. Tryptase mast cells and extracellular tryptase were often associated with areas of early and more advanced stages of calcification. Our results lead to the conclusion that the tryptase mast cells play a major role in the pineal calcification process as sites where this process starts and as a source of production of numerous biologically active substances including tryptase that participate in calcification.

Isolated placental vessel response to vascular endothelial growth factor and placenta growth factor in normal and growth-restricted pregnancy.

Vascular endothelial growth factor (VEGF) and placenta growth factor (PlGF) cause vasodilation. We examined the vasomotor response of isolated placental vessels to VEGF and PlGF in normal (group I) and intrauterine growth retardation (IUGR)-complicated pregnancy (group II). Rings of vessels were prepared in vitro and mounted on the vessel myograph plunged in tissue bath. The magnitude of dilation to increased doses of VEGF and PlGF has been studied. VEGF is a more potent vasodilator than PlGF. Both, VEGF- and PlGF-induced vasorelaxation was diminished in the IUGR (group II) nearly by half, compared to control (group I). Relative placental nitric oxide deficiency, or decreased sensitivity to VEGF and PlGF may contribute to the development of high impedance fetoplacental circulation.