COVID-19 and Oxidative Stress

Pathogenesis of the novel coronavirus infection COVID-19 is the subject of active research around the world. COVID-19 caused by the SARS-CoV-2 is a complex disease in which interaction of the virus with target cells, action of the immune system and the body’s systemic response to these events are closely intertwined. Many respiratory viral infections, including COVID-19, cause death of the infected cells, activation of innate immune response, and secretion of inflammatory cytokines. All these processes are associated with the development of oxidative stress, which makes an important contribution to pathogenesis of the viral infections. This review analyzes information on the oxidative stress associated with the infections caused by SARS-CoV-2 and other respiratory viruses. The review also focuses on involvement of the vascular endothelium in the COVID-19 pathogenesis.

[Risk factors for the early development of septic shock in patients with severe COVID-19]

AIM

In a retrospective study, we evaluated factors associated with the early development of septic shock in patients with severe COVID-19.

MATERIALS AND METHODS

We collected medical records of the intensive care unit patients submitted by the local COVID-19 hospitals across Russia to the Federal Center for the Critical Care at the Sechenov First Moscow State Medical University (Sechenov University). Septic shock in crticially ill patients requiring mechanical ventilation was defined as a need in vasopressors to maintain blood pressure.

RESULTS

We studied 1078 patients with severe COVID-19 who were admitted to the intensive care units for respiratory support. There were 611 males and 467 females. The mean age was 61.013.7 years. Five hundred twenty five medical records (48.7%) were received from the Moscow hospitals, 159 (14.7%) from the Moscow region, and 394 (36.5%) from the hospitals located in 58 regions of the Russian Federation. In 613 (56.9%) patients, diagnosis of SARS-CoV-2 infection was confirmed by PCR, and in the other cases it was established on the basis of the clinical picture and the results of the chest CT scan. Septic shock developed in 214 (19.9%) of 1078 patients. In the logistic regression model, the risk of septic shock in patients older than 50 years was higher than in patients of a younger age (OR 2.34; 95% CI 1.533.67; p0.0001). In patients with more severe SARS-CoV-2 infection, there was an increase in the prevalence of cardiovascular diseases, including coronary heart disease and atrial fibrillation, type 2 diabetes and malignant tumors. The risk of septic shock in patients with three or more concomitant diseases was higher than in patients without any concomitant chronic diseases (OR 1.76; 95% CI 1.762.70).

CONCLUSION

The risk of septic shock in patients with acute respiratory distress syndrome induced by SARS-CoV-2 is higher in patients older than 50 years with concomitant diseases, although a severe course of the disease is also possible in younger patients without any concomitant disorders.

[Clinicopatological variants and risk factors for chronic kidney disease in rheumatoid arthritis]

Recent studies have shown a high risk of chronic kidney disease and associated cardiovascular complications in patients with rheumatoid arthritis (RA), which determines the prognosis. However, the prevalence of chronic kidney disease (CKD) in RA has not been established in the Russians.

AIM

Study was to examine the prevalence, risk factors and histological variants of CKD in RA.

MATERIALS AND METHODS

180 patients with rheumatoid arthritis were observed in the Tareev clinic of nephrology, for the period from 2014 to 2019 years. Age, gender, duration of RA, drug therapy, ESR, CRP, DAS28, renal function, proteinuria, histological variants were analyzed. Of the common population risk factors for CKD arterial hypertension, weight index, serum lipids and glucose levels were also assessed.

RESULTS

The prevalence of CKD in RA was 19.7%. Age, presence and stage of arterial hypertension, an increase in body mass index, as well as high rates of disease activity ESR, CRP, DAS28 score and duration of RA were risk factors of CKD in RA. Age, duration of the disease, stage of AH and hypercholesterolemia were risk factors in multifactorial regression analysis. Amyloidosis was the most common histologic pattern (50.0%), followed by chronic glomerulonephritis (30.4%) and tubulo-interstitial nephritis (19.6%). Among chronic glomerulonephritis mesangial glomerulonephritis was the most frequent. Renal amyloidosis was associated with a duration of RA, presence of systemic symptoms and CRP level. An isolated decrease in GFR of less than 60 ml/min was detected in 31 (36.0%) out of 86 patients. Сonclusion. The risk factors for CKD in patients with RA are activity and duration of the disease In addition to common population factors. Amyloidosis was the most common histologic pattern associated with duration of RA and inflammatory proteins levels.

Autoimmune liver disease (primary biliary cholangitis/autoimmune hepatitis-overlap) associated with sarcoidosis (clinical cases and literature review)

Clinical features of overlap autoimmune hepatitis/primary biliary cholangitis and morphological-proved sarcoid lesions (lungs, lymph nodes, skin) were performed. Data of long-term clinical observation presented in comparison with the results of laboratory datas, instrumental and morphological studies of liver tissue, lungs, skin. The modern aspects of pathogenesis of association autoimmune and granulomatous diseases arediscussed on the example of clinical cases of combination of cholestatic variants of autoimmune hepatitis and generalized sarcoidosis. Keywords: sarcoidosis, autoimmune hepatitis, primary biliary cholangitis, primary biliary cholangitis-autoimmune hepatitis-overlap, extrahepatic manifestations.

Mitochondria-Targeted Antioxidant SkQ1 (10-(6´-Plastoquinonyl)decyltriphenylphosphonium Bromide) Inhibits Mast Cell Degranulation in vivo and in vitro

The therapeutic effect of mitochondria-targeted antioxidant 10-(6´-plastoquinonyl)decyltriphenylphosphonium bromide (SkQ1) in experimental models of acute inflammation and wound repair has been shown earlier. It was suggested that the antiinflammatory activity of SkQ1 is related to its ability to suppress inflammatory activation of the vascular endothelium and neutrophil migration into tissues. Here, we demonstrated that SkQ1 inhibits activation of mast cells (MCs) followed by their degranulation and histamine release in vivo and in vitro. Intraperitoneal injections of SkQ1 in the mouse air-pouch model reduced the number of leukocytes in the air-pouch cavity and significantly decreased the histamine content in it, as well as suppressing MC degranulation in the air-pouch tissue. The direct effect of SkQ1 on MCs was studied in vitro in the rat basophilic leukemia RBL-2H3 cell line. SkQ1 inhibited induced degranulation of RBL-2H3 cells. These results suggest that mitochondrial reactive oxygen species are involved in the activation of MCs. It is known that MCs play a crucial role in regulation of vascular permeability by secreting histamine. Suppression of MC degranulation by SkQ1 might be a significant factor in the antiinflammatory activity of this mitochondria-targeted antioxidant.

Clinical significance of the determination of surfactant proteins A and D in assessing the activity of lung sarcoidosis

The results of a clinical study showing the importance of surfactant proteins A and D in assessing the activity and progression of idiopathic pulmonary fibrosis and chronic lung sarcoidosis are presented. Aim. To study the clinical significance of SP-A, SP-D in assessing the activity of idiopathic pulmonary fibrosis and sarcoidosis. We examined 81 patients with morphologically confirmed diagnoses of idiopathic pulmonary fibrosis (ILF) and sarcoidosis, a control group of 20 healthy individuals. The MSCT of the thoracic organs of the chest was performed, the diffusivity of the lungs was examined, oxygen saturation was determined. In the serum, the surfactant proteins SP-A and SP-D were determined by the enzyme-linked immunosorbent assay. Results. A significant increase in SP-A and SP-D (p

Clinical features of cardiac lesion in patients with generalized sarcoidosis

The article presents a clinical observation of two patients with generalized sarcoidosis. The woman typical granulomatous changes in the lungs and lymph nodes combined with atrial fibrillation, kidney failure and hereditary thrombophilia, men with atherosclerotic coronary arteries, re-myocardial infarction, cholestasis, tubulointerstitial nephritis. The accession of systemic manifestations was accompanied by increase of level of angiotensin-converting enzyme in the blood serum, morphological examination of lung tissue in both cases there were high histological activity of vasculitis and granulomatous inflammation. Extrapulmonary symptoms regressed when conducting immunosuppressive therapy. Discusses modern aspects of diagnosis of sarcoidosis in clinical practice.

Comparison of the Effects of Mitochondria-Targeted Antioxidant 10-(6'-Plastoquinonyl)Decyltriphenylphosphonium Bromide (SkQ1) and a Fragment of its Molecule Dodecyltriphenylphosphonium on Carrageenan-Induced Acute Inflammation in Mouse Model of Subcuteneous Air Pouch

The effect of mitochondria-targeted antioxidant 10-(6'-plastoquinonyl) decyltriphenylphosphonium bromide (SkQ1) and its fragment dodecyltriphenylphosphonium (C12TPP), weak uncouplers of respiration and oxidative phosphorylation, was studied using a mouse model of carrageenan-induced acute inflammation in the subcutaneous air pouch. In our model, SkQ1 demonstrated a strong anti-inflammatory effect that manifested in a decrease in the absolute number of inflammatory cells, mainly neutrophils, and their relative number in parallel with an increase in macrophages and mast cell content in the inflammatory exudate. The concentration of proinflammatory cytokine IL-6 in the exudate also tended to decrease. C12TPP produced no significant effect on the inflammation process.

Low concentration of uncouplers of oxidative phosphorylation decreases the TNF-induced endothelial permeability and lethality in mice

Mitochondrial dysfunctions occur in many diseases linked to the systemic inflammatory response syndrome (SIRS). Mild uncoupling of oxidative phosphorylation is known to rescue model animals from pathologies related to mitochondrial dysfunctions and overproduction of reactive oxygen species (ROS). To study the potential of SIRS therapy by uncoupling, we tested protonophore dinitrophenol (DNP) and a free fatty acid (FFA) anion carrier, lipophilic cation dodecyltriphenylphosphonium (C₁₂TPP) in mice and in vitro models of SIRS. DNP and C₁₂TPP prevented the body temperature drop and lethality in mice injected with high doses of a SIRS inducer, tumor necrosis factor (TNF). The mitochondria-targeted antioxidant plastoquinonyl decyltriphenylphosphonium (SkQ1) which also catalyzes FFA-dependent uncoupling revealed similar protective effects and downregulated expression of the NFκB-regulated genes (VCAM1, ICAM1, MCP1, and IL-6) involved in the inflammatory response of endothelium in aortas of the TNF-treated mice. In vitro mild uncoupling rescued from TNF-induced endothelial permeability, disassembly of cell contacts and VE-cadherin cleavage by the matrix metalloprotease 9 (ММР9). The uncouplers prevented TNF-induced expression of MMP9 via inhibition of NFκB signaling. Water-soluble antioxidant Trolox also prevented TNF-induced activation and permeability of endothelium in vitro via inhibition of NFκB signaling, suggesting that the protective action of the uncouplers is linked to their antioxidant potential.

Mitochondria-Targeted Antioxidant SkQR1 Reduces TNF-Induced Endothelial Permeability in vitro

Prolonged or excessive increase in the circulatory level of proinflammatory tumor necrosis factor (TNF) leads to abnormal activation and subsequent damage to endothelium. TNF at high concentrations causes apoptosis of endothelial cells. Previously, using mitochondria-targeted antioxidants of SkQ family, we have shown that apoptosis of endothelial cells is dependent on the production of reactive oxygen species (ROS) in mitochondria (mito-ROS). Now we have found that TNF at low concentrations does not cause cell death but activates caspase-3 and caspase-dependent increase in endothelial permeability in vitro. This effect is probably due to the cleavage of β-catenin - an adherent junction protein localized in the cytoplasm. We have also shown that extracellular matrix metalloprotease 9 (MMP9) VE-cadherin shedding plays a major role in the TNF-induced endothelial permeability. The mechanisms of the caspase-3 and MMP9 activation are probably not related to each other since caspase inhibition did not affect VE-cadherin cleavage and MMP9 inhibition had no effect on the caspase-3 activation. Mitochondria-targeted antioxidant SkQR1 inhibited TNF-induced increase in endothelial permeability. SkQR1 also inhibited caspase-3 activation, β-catenin cleavage, and MMP9-dependent VE-cadherin shedding. The data suggest that mito-ROS are involved in the increase in endothelial permeability due to the activation of both caspase-dependent cleavage of intracellular proteins and of MMP9-dependent cleavage of the transmembrane cell-to-cell contact proteins.

Priming of Human Neutrophils Is Necessary for Their Activation by Extracellular DNA

Extracellular plasma DNA is thought to act as a damage-associated molecular pattern causing activation of immune cells. However, purified preparations of mitochondrial and nuclear DNA were unable to induce neutrophil activation in vitro. Thus, we examined whether granulocyte-macrophage colony-stimulating factor (GM-CSF) acting as a neutrophil priming agent can promote the activation of neutrophils by different types of extracellular DNA. GM-CSF pretreatment greatly increased p38 MAPK phosphorylation and promoted CD11b/CD66b expression in human neutrophils treated with mitochondrial and, to a lesser extent, with nuclear DNA. Our experiments clearly indicate that GM-CSF-induced priming of human neutrophils is necessary for their subsequent activation by extracellular DNA.

Mitochondria-targeted antioxidant SkQ1 improves impaired dermal wound healing in old mice

The process of skin wound healing is delayed or impaired in aging animals. To investigate the possible role of mitochondrial reactive oxygen species (mtROS) in cutaneous wound healing of aged mice, we have applied the mitochondria-targeted antioxidant SkQ1. The SkQ1 treatment resulted in accelerated resolution of the inflammatory phase, formation of granulation tissue, vascularization and epithelization of the wounds. The wounds of SkQ1-treated mice contained increased amount of myofibroblasts which produce extracellular matrix proteins and growth factors mediating granulation tissue formation. This effect resembled SkQ1-induced differentiation of fibroblasts to myofibroblast, observed earlier in vitro. The Transforming Growth Factor beta (TGFβ)produced by SkQ1-treated fibroblasts was found to stimulated motility of endothelial cells in vitro, an effect which may underlie pro-angiogenic action of SkQ1 in the wounds. In vitro experiments showed that SkQ1 prevented decomposition of VE-cadherin containing contacts and following increase in permeability of endothelial cells monolayer, induced by pro-inflammatory cytokine TNF. Prevention of excessive reaction of endothelium to the pro-inflammatory cytokine(s) might account for anti-inflammatory effect of SkQ1. Our findings point to an important role of mtROS in pathogenesis of age-related chronic wounds.

Pure Mitochondrial DNA Does Not Activate Human Neutrophils in vitro

Excessive activation of the innate immune system often leads to fatal consequences and can be considered as one of the phenoptotic events. After traumatic injury, various components of mitochondria are released into the circulation and stimulate myeloid cells of the innate immunity. Presumably, mitochondrial DNA (mtDNA) might activate immune cells (Zhang, Q., et al. (2010) Nature, 464, 104-107). In the present study, we investigated the role of mtDNA as a direct activator of human neutrophils, as well as a prognostic marker in patients with severe trauma. Quantitative determination of mtDNA in the plasma of these patients revealed its significant increase (p < 0.02) in the group of survivors compared to non-survivors. Highly purified mtDNA was not able to induce activation of human neutrophils, thus possibly indicating the existence of additional factor(s) ensuring the recognition of mtDNA as a damage-associated molecular pattern.

Low Concentrations of Uncouplers of Oxidative Phosphorylation Prevent Inflammatory Activation of Endothelial Cells by Tumor Necrosis Factor

In endothelial cells, mitochondria play an important regulatory role in physiology as well as in pathophysiology related to excessive inflammation. We have studied the effect of low doses of mitochondrial uncouplers on inflammatory activation of endothelial cells using the classic uncouplers 2,4-dinitrophenol and 4,5,6,7-tetrachloro-2-trifluoromethylbenzimidazole, as well as the mitochondria-targeted cationic uncoupler dodecyltriphenylphosphonium (C12TPP). All of these uncouplers suppressed the expression of E-selectin, adhesion molecules ICAM1 and VCAM1, as well as the adhesion of neutrophils to endothelium induced by tumor necrosis factor (TNF). The antiinflammatory action of the uncouplers was at least partially mediated by the inhibition of NFκB activation due to a decrease in phosphorylation of the inhibitory subunit IκBα. The dynamic concentration range for the inhibition of ICAM1 expression by C12TPP was three orders of magnitude higher compared to the classic uncouplers. Probably, the decrease in membrane potential inhibited the accumulation of penetrating cations into mitochondria, thus lowering the uncoupling activity and preventing further loss of mitochondrial potential. Membrane potential recovery after the removal of the uncouplers did not abolish its antiinflammatory action. Thus, mild uncoupling could induce TNF resistance in endothelial cells. We found no significant stimulation of mitochondrial biogenesis or autophagy by the uncouplers. However, we observed a decrease in the relative amount of fragmented mitochondria. The latter may significantly change the signaling properties of mitochondria. Earlier we showed that both classic and mitochondria-targeted antioxidants inhibited the TNF-induced NFκB-dependent activation of endothelium. The present data suggest that the antiinflammatory effect of mild uncoupling is related to its antioxidant action.

Mitochondria-targeted antioxidants prevent TNFα-induced endothelial cell damage

Increased serum level of tumor necrosis factor α (TNFα) causes endothelial dysfunction and leads to serious vascular pathologies. TNFα signaling is known to involve reactive oxygen species (ROS). Using mitochondria-targeted antioxidant SkQR1, we studied the role of mitochondrial ROS in TNFα-induced apoptosis of human endothelial cell line EAhy926. We found that 0.2 nM SkQR1 prevents TNFα-induced apoptosis. SkQR1 has no influence on TNFα-dependent proteolytic activation of caspase-8 and Bid, but it inhibits cytochrome c release from mitochondria and cleavage of caspase-3 and its substrate PARP. SkQ analogs lacking the antioxidant moieties do not prevent TNFα-induced apoptosis. The antiapoptotic action of SkQR1 may be related to other observations made in these experiments, namely SkQR1-induced increase in Bcl-2 and corresponding decrease in Bax as well as p53. These results indicate that mitochondrial ROS production is involved in TNFα-initiated endothelial cell death, and they suggest the potential of mitochondria-targeted antioxidants as vasoprotectors.

[Clinical value of surfactant protein D as a biomarker of pulmonary fibrosis in patients with scleroderma systematica in relation to the presence of gastroesophageal reflux]

AIM

To study the role of serum surfactant protein D (SP-D) as a biomarker of lung injury in scleroderma systematica (SDS) in relation to the presence of gastroesophageal reflux (GER).

SUBJECTS AND METHODS

Fifty-six patients (mean age 46±14 years) with diffuse and circumscribed SDS were examined and underwent pulmonary functional tests, X-ray and, if lung injury was present, high-resolution computed tomography of the lung, echocardiography, gastroduodenoscopy, and barium X-ray of the esophagus; an enzyme-linked immunosorbent assay was used to determine serum SP-D levels.

RESULTS

SP-D concentrations significantly correlate with the presence of lung injury in SDS and are significantly higher in the presence of pulmonary fibrosis and the signs of frosted glass and honeycomb lung patterns. SP-D levels were higher in the patients with lung injury and SDS in the group of those with pulmonary fibrosis and GER than in the group of pulmonary fibrosis patients without the latter.

CONCLUSION

Serum SP-D may be considered in a number of biomarkers for the severity of lung injury in SDS, including GER-associated lung injury.

[Current optimization of combined therapy for chronic obstructive pulmonary disease]

Testing the new combined bronchodilator Anoro Ellipta in different clinical trials gives to its high clinical efficacy and safety in chronic obstructive pulmonary disease. The drug contains the molecules of sustained-release selective β2-adrenergic receptor agonist (vilanterol) and a muscarinic cholinergic receptor antagonist (umeclidinium bromide). The bronchodilating mechanisms of umeclidinium bromide are in the competitive inhibition of the binding of acetylcholine with muscarinic acetylcholine receptors of airway smooth muscles whereas in those of vilanterol are in that with the stimulation of intracellular adenylate cyclase. On days 1 and 24 after inhalation of the first dose of vilanterol and umeclidinium bromide, there was a significant increase in the forced expiratory volume in one second as compared to placebo. No clinical effects on QT interval on an electrocardiogram and cardiac rhythm were found. The benefits of an inhalation device (Ellipta) are its innovation design ensuring the effective delivery of an aerosol dose into the airway, convenience, and simplicity.

Role of mitochondrial reactive oxygen species in age-related inflammatory activation of endothelium

Vascular aging is accompanied by increases in circulatory proinflammatory cytokines leading to inflammatory endothelial response implicated in early atherogenesis. To study the possible role of mitochondria-derived reactive oxygen species (ROS) in this phenomenon, we applied the effective mitochondria-targeted antioxidant SkQ1, the conjugate of plastoquinone with dodecyltriphenylphosphonium. Eight months treatment of (CBAxC57BL/6) F1 mice with SkQ1 did not prevent age-related elevation of the major proinflammatory cytokines TNF and IL-6 in serum, but completely abrogated the increase in adhesion molecule ICAM1 expression in aortas of 24-month-old animals. In endothelial cell culture, SkQ1 also attenuated TNF-induced increase in ICAM1, VCAM, and E-selectin expression and secretion of IL-6 and IL-8, and prevented neutrophil adhesion to the endothelial monolayer. Using specific inhibitors to transcription factor NF-κB and stress-kinases p38 and JNK, we demonstrated that TNF-induced ICAM1 expression depends mainly on NF-κB activity and, to a lesser extent, on p38. SkQ1 had no effect on p38 phosphorylation (activation) but significantly reduced NF-κB activation by inhibiting phosphorylation and proteolytic cleavage of the inhibitory subunit IκBα. The data indicate an important role of mitochondrial reactive oxygen species in regulation of the NF-κB pathway and corresponding age-related inflammatory activation of endothelium.

[Interstitial pulmonary fibrosis: the role of angiogenic factors, the inhibitory pathways of progression]

AIM

To assess the role of angiogenic factors (vascular endothelial growth factor (VEGF) and endothelin-1 (ET-1) in interstitial lung diseases (ILD), such as fibrosing alveolitis, sarcoidosis.

SUBJECTS AND METHODS

The blood levels of endothelial dysfunction and neoangiogenesis markers (ET-1 and VEGF) were investigated in 96 patients with different clinical forms of ILD at it different stages; the found changes were compared with the clinical and morphological manifestations of the disease.

RESULTS

It has been ascertained that regardless of the clinical type of ILD, there is a correlation between the blood levels of VEGF and ET-1 and the intensity of lung neoangiogenesis, the expression of VEGF by the endothelium of newly formed blood vessels, the production of angiogenic factors, the degree of endothelial dysfunction, the extent of pulmonary fibrosis, the degree of pulmonary vascular remodeling, and the severity of pulmonary hypertension. The findings suggest that the markers of neoangiogenesis play an important role in the mechanisms of ILD progression.

CONCLUSION

The study of these parameters in the blood may be used to clarify the activity and prognosis of ILD.

[Characteristics of ischemic stroke in patients with congenital anomalies of the circle of Willis]

The study included 76 patients with ischemic stroke in the carotid system (56 patients) and in the vertebrobasilar system (20 patients). The magnetic resonance angiography (MRA) revealed congenital anomalies of Willis circle in 31 patients. These anomalies were stratified as follows: back trifurcation of the internal carotid artery (ICA) (19 patients), anterior trifurcation of the ICA (4 patients), the combination of anterior trifurcation of the one of ICA and posterior trifurcation of the other ICA (4 patients), double back trifurcation of ICA (2 patients), the normal structure of the circle of Willis (45 patients). Patients with anomalies of the circle of Willis scored significantly higher on the Neurological deficit scale NIH-NINDS. Despite the lack of significant differences in the size of lesions in 2 groups, the foci in patients with the abnormalities of the circle of Willis were frequently localized in adjacent blood supply zones. The signs of vascular encephalopathy were seen as well. The data obtained suggest that the presence of anomalies in the circle of Willis is a risk factor, together with in the additional adversities, including iatrogenic factor, for the development of hemodynamic ischemic stroke.

Scavenging of reactive oxygen species in mitochondria induces myofibroblast differentiation

The goal of this study was to investigate the possible role of reactive oxygen species (ROS) in signaling, in modulation of the cytoskeleton, and in differentiation of fibroblasts. For this purpose, we have applied a novel mitochondria-targeted antioxidant: plastoquinone conjugated with decyltriphenylphosphonium (SkQ1). This antioxidant at nanomolar concentration prevented ROS accumulation and cell death induced by H(2)O(2) in fibroblasts. We found that scavenging of ROS produced by mitochondria activated the Rho/ROCK/LIMK signaling pathway that was followed by phosphorylation of cofilin and stabilization of actin stress fibers. The mitochondria-targeted antioxidant induced differentiation of human subcutaneous fibroblasts to myofibroblasts as revealed by expression of fibronectin isoform (EDA-FN) and smooth muscle actin (α-SMA). This effect was shown to be mediated by transforming growth factor β1 (TGFβ1), which was activated by matrix metalloprotease 9 (MMP9) in the culture medium. Scavenging of ROS stimulated secretion of MMP9 rather than its processing. The same effect was achieved by the nontargeted antioxidant Trolox at higher concentration, but the thiol antioxidant N-acetylcysteine (NAC) inhibited MMP activity and was not able to induce myofibroblast differentiation. The myofibroblast phenotype was supported due to autocrine TGFβ1-dependent stimulation after removal of SkQ1. It is concluded that ROS scavenging in mitochondria induces TGFβ1-dependent myofibroblast differentiation.

Novel mitochondria-targeted antioxidants, "Skulachev-ion" derivatives, accelerate dermal wound healing in animals

It is shown that the novel mitochondria-targeted antioxidant SkQ1, (10-(6'-plastoquinonyl) decyltriphenylphosphonium) stimulates healing of full-thickness dermal wounds in mice and rats. Treatment with nanomolar doses of SkQ1 in various formulations accelerated wound cleaning and suppressed neutrophil infiltration at the early (7 h) steps of inflammatory phase. SkQ1 stimulated formation of granulation tissue and increased the content of myofibroblasts in the beginning of regenerative phase of wound healing. Later this effect caused accumulation of collagen fibers. Local treatment with SkQ1 stimulated re-epithelization of the wound. Lifelong treatment of mice with SkQ1 supplemented with drinking water strongly stimulated skin wounds healing in old (28 months) animals. In an in vitro model of wound in human cell cultures, SkQ1 stimulated movement of epitheliocytes and fibroblasts into the "wound". Myofibroblast differentiation of subcutaneous fibroblasts was stimulated by SkQ1. It is suggested that SkQ1 stimulates wound healing by suppression of the negative effects of oxidative stress in the wound and also by induction of differentiation. Restoration of regenerative processes in old animals is consistent with the "rejuvenation" effects of SkQ1, which prevents some gerontological diseases.

Mitochondria as source of reactive oxygen species under oxidative stress. Study with novel mitochondria-targeted antioxidants--the "Skulachev-ion" derivatives

Production of reactive oxygen species (ROS) in mitochondria was studied using the novel mitochondria-targeted antioxidants (SkQ) in cultures of human cells. It was shown that SkQ rapidly (1-2 h) and selectively accumulated in mitochondria and prevented oxidation of mitochondrial components under oxidative stress induced by hydrogen peroxide. At nanomolar concentrations, SkQ inhibited oxidation of glutathione, fragmentation of mitochondria, and translocation of Bax from cytosol into mitochondria. The last effect could be related to prevention of conformational change in the adenine nucleotide transporter, which depends on oxidation of critical thiols. Mitochondria-targeted antioxidants at nanomolar concentrations prevented accumulation of ROS and cell death under oxidative stress. These effects required 24 h or more (depending on the cell type) preincubation, and this was not related to slow induction of endogenous antioxidant systems. It is suggested that SkQ slowly accumulates in a small subpopulation of mitochondria that have decreased membrane potential and produce the major part of ROS under oxidative stress. This population was visualized in the cells using potential-sensitive dye. The possible role of the small fraction of "bad" mitochondria in cell physiology is discussed.

[Clinical significance of markers of endothelial dysfunction and angiogenesis in progressing of the lung interstitial diseases]

The data obtained suggest an important role of the FRES and ET-1 in progressing of the lung interstitial diseases; they can be used as diagnostic criteria of the disease activity, risk of pulmonary hypertension, and extra-pulmonary manifestations.

[Cerebral sodium-uretic peptide: pathogenetic and clinical significance in pulmonary arterial hypertension associated with interstitial diseases of the lungs]

Sodium-uretic peptides (SUP) are the main humoral system opposing pathological remodeling of vascular bed in diseases of cardiovascular system and kidneys. In the paper, pathogenetic and clinical significance of the cerebral SUP in pulmonary arterial hypertension, including the one associated with interstitial diseases of the lungs.

Generation of new TRAIL mutants DR5-A and DR5-B with improved selectivity to death receptor 5

TRAIL (tumor necrosis factor (TNF) related apoptosis-inducing ligand) has been introduced as an extrinsic pathway inducer of apoptosis that does not have the toxicities of Fas and TNF. However, the therapeutic potential of TRAIL is limited because of many primary tumor cells are resistant to TRAIL. Despite intensive investigations, little is known in regards to the mechanisms underlying TRAIL selectivity and efficiency. A major reason likely lies in the complexity of the interaction of TRAIL with its five receptors, of which only two DR4 and DR5 are death receptors. Binding of TRAIL with decoy receptors DcR1 and DcR2 or soluble receptor osteoprotegerin (OPG) fail to induce apoptosis. Here we describe design and expression in Escherichia coli of DR5-selective TRAIL variants DR5-A and DR5-B. The measurements of dissociation constants of these mutants with all five receptors show that they practically do not interact with DR4 and DcR1 and have highly reduced affinity to DcR2 and OPG receptors. These mutants are more effective than wild type TRAIL in induction of apoptosis in different cancer cell lines. In combination with the drugs targeted to cytoskeleton (taxol, cytochalasin D) the mutants of TRAIL induced apoptosis in resistant Hela cells overexpressing Bcl-2. The novel highly selective and effective DR5-A and DR5-B TRAIL variants will be useful in studies on the role of different receptors in TRAIL-induced apoptosis in sensitive and resistant cell lines.

[Endothelin-1 and brain natriuretic peptide in the development of pulmonary hypertension in interstitial lung diseases]

AIM

To study the plasma concentration of brain natriuretic peptide (BNP) and endothelin-1 (ET-1) as markers of pulmonary hypertension (PH) developed in interstitial lung diseases (ILD).

SUBJECTS AND METHODS

Along with physical examination, 97 patients with ILD underwent measurements of the plasma concentrations of BNP and ET-1, 6-minute walk test, external respiration function test, echocardiography, by measuring pulmonary artery systolic pressure (P(syst)), and chest multispiral computed tomography, by estimating the mean diameter of the pulmonary artery trunk.

RESULTS

The plasma concentration of ET-1 proved to be significantly higher in the presence of active lung lesion (5.2 +/- 3.9 and 2.8 +/- 1.8 pg/ml; p = 0.0001). In patients with ILD, persistent PH was associated with the significantly elevated plasma concentrations of BNP (69.3 +/- 341.35 and 23.7 +/- 26.69 pg/ml; p = 0.018). The increase of plasma BNP concentrations correlated with the shorter distance covered during a 6-minute walk test and diminished functional vital capacity.

CONCLUSION

The increased plasma levels of ET-1 in ILD reflects the transient pulmonary artery pressure elevation associated with the activity of the pulmonary process while those of BNP are indicative of developed persistent PH.

[Estimation of plasmic concentration of the brain natriuretic peptide in interstitial pulmonary diseases with pulmonary hypertension: clinical role]

AIM

To study a plasmic concentration of the brain natriuretic peptide (BNUP) in patients with interstitial pulmonary disease (IPD) as a possible diagnostic parameter in pulmonary hypertension (PH).

MATERIAL AND METHODS

Plasmic BNUP concentration, external respiration function were studied in 24 patients with IPD. The following tests were also made: 6-min walk, echocardiography (echo-CG) with estimation of systolic pressure in the pulmonary artery, multislice computed tomography of the chest with measurement of the mean diameter of the pulmonary artery trunk.

RESULTS

As shown by echo-CG and chest MSCT half of the IPD patients had PH. IPD patients with PH had a significant elevation of plasmic BNUP concentration which, in intact left ventricular contractile function indicates development of secondary PH characterized by reduction of volume parameters of the respiratory pulmonary function. The rise of BNUP concentration correlated with reduction of 6-min walk distance and functional lung capacity.

CONCLUSION

Plasmic BNUP can be used for diagnosis of PH in IPD patients.

[Emotional stress in the development of experimental hemorrhagic stroke in rats with different resistance to stress]

Individual behavioral characteristics of rats in the open-field test reflect their resistance to emotional stress and determine the severity of neurological disorders during intracerebral hemorrhage. Stress-resistant rats are characterized by a more rapid restoration of neurological status and disappearance of locomotor and coordination disturbances on day 7 after unilateral hemorrhage stroke in the caudate nucleus as compared to stress-predisposed animals. After hemorrhage stroke in the caudate nucleus, changes in vessels and neurons of the contralateral sensorimotor cortex were more pronounced in stress-predisposed passive rats than in stress-resistant active animals. The newly formed capillaries were not seen in stress-predisposed specimens. To day 7 of post stress hemorrhage stroke in the caudate nucleus, signs of the involvement of compensatory mechanisms in the contralateral sensorimotor cortex appeared in stress-resistant but not in stress-predisposed rats. This finding suggests the possibility of restoration of structure and normal functioning of neurons.

[Natriuretic peptides in diagnosis of pulmonary hypertension]

Pathogenetic and diagnostic role of natriuretic peptides in different variants of pulmonary hypertension is discussed. Structure, mechanism of action and physiological effects of some natriuretic peptides and their role in diagnosis and monitoring of the course of pulmonary hypertension are described.

[Hippocratic fingers: clinical importance and differential diagnosis]

Changing of the distant finger phalanges into the form of a drumstick or fingernails into the form of a watch-glass (hippocratic fingers--HF) presents a well-known clinical phenomenon that suggests the presence of various diseases, especially those associated with hypoxia, i.e. manifested by respiratory and/or heart failure, as well as malignant tumors and subacute infective endocarditis. At the same time, the fact that this clinical phenomenon can accompany other diseases (Crohn's disease, HIV-infection) should be taken into consideration as well. HF often appear ahead of more specific symptoms. In this connection, correct interpretation of this clinical sign, augmented with laboratory tests, allows for early and valid diagnosis.

Effect of oxidative stress on dynamics of mitochondrial reticulum

Fission of the mitochondrial reticulum (the thread-grain transition) and following gathering of mitochondria in the perinuclear area are induced by oxidative stress. It is shown that inhibitors of the respiratory chain (piericidin and myxothiazol) cause fission of mitochondria in HeLa cells and fibroblasts, whereas a mitochondria-targeted antioxidant (MitoQ) inhibits this effect. Hydrogen peroxide also induced the fission, which was stimulated by the inhibitors of respiration and suppressed by MitoQ. In untreated cells, the mitochondrial reticulum consisted of numerous electrically-independent fragments. Prolonged treatment with MitoQ resulted in drastic increase in size and decrease in number of these fragments. Local photodamage of mitochondria caused immediate depolarization of a large fraction of the mitochondrial network in MitoQ-treated cells. Our data indicate that the thread-grain transition of mitochondria depends on production of reactive oxygen species (ROS) in initial segments of the respiratory chain and is a necessary step in the process of elimination of mitochondria (mitoptosis).

Ultrastructure of the Sensorimotor Cortex of Pubertal Offspring of Alcoholic Male Rats

The ultrastructure of neurons, astrocytes, and capillaries in the sensorimotor cortex of three-month-old offspring of alcoholic male rats (8 g/kg of 50% alcohol solution daily for four weeks) was studied. Apart from signs of delayed maturation of nerve and glial cell processes, some cortical areas showed destructive changes affecting a proportion of neurons along with elements of compensatory-adaptive processes in some nerve cells. Membrane and myelin-like intranuclear inclusions and changes in the Golgi complex were characteristic features of the damage to populations of cortical neurons. Swelling of astrocytes, deformation of capillaries and changes in their ultrastructure, with accumulation of atypical inclusions in pericapillary astrocyte processes, degraded reciprocal exchange processes between blood and neurons. The possible role of the ischemic-hypoxic factor in delayed changes in the ultrastructure of the sensorimotor cortex in the offspring of alcoholic males is discussed.

Structure of the sensorimotor area of the cerebral cortex in the offspring of alcoholized rats

Light and electron microscopy and morphometry were used to study the characteristics of the cytoarchitectonics of the sensorimotor cortex and the structures of neurons and their dendrites in 21- and 30-day-old baby rats born to chronically alcoholized females and males. Three categories of morphological changes were identified: signs of delayed maturation of neurons and dendrites, destructive changes to these structures, and signs of repair processes, with dynamics occurring during postnatal ontogenesis. At age three weeks, apart from delayed maturation of neurons and underdevelopment of the dendritic system, there were also spreading destructive changes. Increasing age was associated with increases in repair processes, though destructive changes to neurons persisted, which is evidence for the delayed action of alcohol intoxication of animals on the structural development of the brain in their offspring.

Structural-functional organization of neurons in the cerebral cortex of rats with different levels of resistance to emotional stress in conditions of exposure to delta sleep-inducing peptide

Wistar rats with different levels of resistance to emotional stress (ES) were subjected to stress and brain sections stained with Nissl cresyl violet were used for quantitative analysis of the structural organization of neurons in layer V of the sensorimotor cortex. Some animals received delta sleep-inducing peptide (DSIP) 1 h before stress. Control ES-susceptible rats, as compared with resistant rats, had lower levels of normochromic and moderately hypochromic neurons. Normochromic neurons were not seen after stress. Rats susceptible to ES showed particularly sharp decreases in moderately hypo- and hyperchromic neurons, along with increases in the proportions of extremely hypo- and hyperchromic neurons, ghost cells, and ischemically altered cells. After administration of DSIP before stress, ischemically altered cells were not seen in any group: the level of reduction of extremely hyperchromic neurons was smaller in ES-susceptible rats than in ES-resistant rats. It is suggested that brain hypoxia plays a particular role in disorganizing the cortex in conditions of ES, while DSIP has both antistress and antihypoxic properties.

Age-Related Structural and Functional Characteristics of Rabbit Hippocampal Neurons During the Formation of Temporal Associations

Spectral analysis (spectral density histograms) of neuron spike activity in the hippocampus of rabbits of different ages revealed trace assimilation of rhythms--an analog of a conditioned reflex to time--after rhythmic stimulation. An association was established between the number of series of periodic electrocutaneous stimulation presented and the extent of trace assimilation of the rhythm, depending on the age of the animal. Trace assimilation of rhythms occurred more slowly in older animals (aged 54-65 months) than in young animals (aged up to one year), predominantly on days 2-3 of experiments after presentation of 2-4 series of rhythmic stimulation, and persisted in a small proportion of cases on the day following stimulation. Periodic stimulation in very old animals (aged 66-85 months) almost completely failed to induce plastic rearrangements of hippocampal neuron activity. Stimulation produced a non-specific trace increase in the frequency of hippocampal baseline neuron activity in old animals. Quantitative and qualitative morphological changes were identified in the nerve and glial cells of the hippocampus of aged rabbits, as compared to young rabbits. It is suggested that the change in the course of mnestic processes seen in animals with aging may be associated with age-related destructive changes in the hippocampus.

[Vasaprostan treatment of fibrosing alveolitis in patients with pulmonary hypertension]

AIM

To study clinical efficacy of vasaprostan in patients with fibrosing alveolitis (FA) complicated by pulmonary hypertension (PH), its effect on functional activity of platelets and endothelium, intensity of free radical processes.

MATERIAL AND METHODS

Seven FA patients were examined. They had either idiopathic FA or FA with diffuse diseases of the connective tissues. The following methods were used to assess the effect: standard clinical tests, high resolution computer tomography, Doppler echocardiography, definition of the complex thrombin-antithrombin (TAT) and thrombocytic factor 4 (TF-4). Generation of oxygen active forms by leukocytes was measured by luminol-dependent chemiluminescence. Morphological verification of the diagnosis was made by the results of open pulmonary biopsies.

RESULTS

Vasaprostan reduced pressure in the pulmonary artery from 31.6 +/- 2.31 to 19.58 +/- 3.90 mm Hg (p < 0.05) and coagulation parameters. TAT decreased after 2 and 8 weeks of treatment from 15.25 +/- 4.5 to 5.1 +/- 0.33 and 2.4 +/- 0.31 pg/ml (p < 0.05). Initially low TF-4 (2.11 +/- 0.39 pg/ml) elevated to the end of the treatment and reached values close to control (4.37 +/- 0.25 pg/ml, p < 0.05). Moreover, vasaprostan enhanced the ability of platelets to inhibit generation of active oxygen forms (from 0.9 +/- 0.18 to 1.23 +/- 0.16 r. u., p < 0.05) and thus depressed activity of lipid peroxidation.

CONCLUSION

Good effect of vasaprostan on platelet activity, free radical processes validates its use in combined treatment of various FA forms for correction of PH, its complications and as an antifibrogenic agent.

[Sensomotor cortex ultrastructure in pubertal offspring of alcoholized male rats]

Neuron, astrocyte and capillary ultrastructure was studied in the sensomotor cortex of 3-month-old offspring of the alcoholized male rats that received 8 g of alcohol prepared as 50% solution per kg of body weight once daily for 4 weeks. In addition to the signs of delayed maturation of neuronal and glial cell processes, some cortical areas demonstrated the destructive changes in a certain portion of neurons and elements of compensatory-adaptive processes in the others. Membranous and myelin-like intranuclear inclusions and marked Golgi complex changes were the characteristic features of the damaged cortical neuronal population. Astrocyte swelling, capillary deformation with their ultrastructural changes, accumulation of atypical inclusions in pericapillary astrocyte processes result in deterioration of bilateral blood-neuronal exchange. Possible role of ischemia-hypoxia factor in long-term disturbances in sensomotor cortex ultrastructure in the offspring of alcoholized male rats is emphasized.

[Markers of thrombophilia in pulmonary fibrosis complicated by pulmonary hypertension]

AIM

To determine the role of enhanced blood coagulation in pathogenesis of pulmonary hypertension (PH) at an early stage of fibrosing alveolitis (FA).

MATERIAL AND METHODS

Clinical, functional, roentgenological, coagulation and immunological examinations were performed in 17 patients with idiopathic FA (IFA), in 6 patients with exogenic allergic alveolitis (EAA), in 15 FA patients with diffuse diseases of the connective tissue (FA-DDCT). The diagnosis was verified with high resolution computed tomography (HRCT). Lesser circulation was assessed by Doppler echocardiography. Morphological impairment of the lungs was specified in all the patients using analysis of the bronchoalveolar lavage. In 9 FA patients the diagnosis was verified at thoracoscopic biopsy of the lung. The control group consisted of 16 healthy volunteers. Thrombin-antithrombin complex (TAT) and thrombocytic factor 4 (TF-4) were estimated with ELISA as stable, highly sensitive markers of thrombophilia.

RESULTS

The TF-4 level was elevated in all IPD patients (p < 0.05), the elevation being highest in FA-DDCT (p < 0.007). With FA progression, TF-4 concentration went down. A weak negative correlation (p < 0.047, r = -0.38) was found with average pressure in the pulmonary artery (PAAP). TAT was higher than control in all the groups (p < 0.05). Maximal TAT values were registered in EAA. If HRCT detected active inflammation and in development of irreversible fibrous changes TAT was higher vs control. A direct correlation between TAT level and PAAP was not found.

CONCLUSION

Disorders in thrombocytic and plasmic links of hemostasis are detectable early in IPD. Stable markers of thrombophilia (TAT and TF-4) reflect activity of inflammation in FA. They can be also used as sensitive diagnostic tests for diagnosis of PH and diagnosis of patients with activated coagulation system in IPD.

[Structure of the brain sensomotor cortex in offspring of rats exposed to alcohol]

The purpose of the present study was to examine the development of sensomotor brain cortex structures in progeny of male and female rats chronically intoxicated by alcohol. Using the methods of light and electron microscopy and morphometry, the peculiarities of sensomotor cortex cytoarchitectonics, structure on neurons and of their dendrites were studied in rats aged 21 and 30 days, which belong to the progeny of chronically alcoholized male and female animals. Three categories of morphological changes were recognized: the signs indicative of a delay in the neuronal and dendritic maturation, their destructive changes and the repair phenomena, which possess their individual dynamics in postnatal ontogenesis. At 3 weeks of age the extensive destructive changes are seen besides the delay in neuronal maturation and dendritic system underdevelopment. Repair processes increase with age, but the neuronal destructive changes persist, suggesting the delayed mode of action of alcohol intoxication of the animals on the structural brain development in their offspring.