Factors of Interleukin-6 Signaling in COVID-19 Patients with Lung Damage of Varying Degrees: A Pilot Study.

Specific features of IL-6 signal transduction were studied in 89 patients with lung damage of varying degrees during the first COVID-19 pandemic wave. The levels of IL-6 signaling components (IL-6, sIL-6R, and sgp130) and highly sensitive C-reactive protein (hsCRP) were examined in patients with intact lungs (CT-0), mild (CT-1), moderate (CT-2), moderate to severe (CT-3), and severe (CT-4) lung damage. Seventy patients were re-examined 3-7 months after discharge from the hospital. The IL-6 and hsCRP levels increased several times with severing lung damage severity. In patients with CT-3, sIL6-R increased statistically significantly and remained high in CT-4 patients. sgp130 levels were lower in CT-1 and CT-2 patients and higher in CT-3 and CT-4 patients compared to CT-0 patients. We revealed a positive correlation between IL-6 and hsCRP levels in CT-1, CT-2, and CT-3 patients. In CT-3 patients, sIL-6R levels positively correlated with IL-6 concentration. The studied parameters decreased considerably in all patients 3-7 months after discharge. It can be suggested that IL-6 classic-signaling is predominant in CT-1 and CT-2, while trans-signaling prevails in CT-3. Disorders in regulatory mechanisms of IL-6 signaling occur in CT-4, which prevents physiological elimination of IL-6 hyperactivity. The results obtained are preliminary and require a broader study.

Interleukin 6 Signalling in Heart Failure With Preserved and Reduced Ejection Fraction.

AIM: Identification of interleukin-6 (IL-6) signaling pathways in patients with chronic heart failure (CHF). MATERIAL AND METHODS: The diversity of IL-6 effects is due to the presence of classical signaling and trans-signaling pathways. The study included 164 patients with CHF hospitalized for acute decompensated heart failure (ADHF), of which 129 had reduced left ventricular ejection fraction (HFrEF), and 35 had preserved ejection fraction (HFpEF). Blood concentrations of IL-6, soluble IL-6 receptor (sIL-6R), soluble transducer protein gp130 (sgp130), and high-sensitivity C-reactive protein (hsCRP) were measured. RESULTS: Patients with HFpEF had lower concentrations of IL-6 (6.15 [2.78, 10.65] pg/ml) and hsCRP (11.27 [5.84, 24.40] mg/ml) than patients with HFrEF (9.20 [4.70; 15.62] pg/ml and 17.23 [8.70; 34.51 mg/ml], respectively). In contrast, concentrations of rIL-6R were higher in HFpEF (59.06 [40.00; 75.85] ng/ml) than in HFrEF (49.15 [38.20; 64.89] ng/ml). Concentrations of sgp130 were not significantly different. In patients with HFrEF, positive correlations were found between the concentrations of IL-6 and hsCRP, IL-6 and rIL-6R, and IL-6 and sgp130, while in patients with HFpEF, there was a correlation only between IL-6 and hsCRP, which appeared stronger than in patients with HFrEF (r=0.698; p<0.001 and r=0.297; p<0.05, respectively). CONCLUSION: Classical IL-6 signaling and trans-signaling are expressed to different degrees in patients with HFrEF and HFpEF in ADHF. The results of the study supplement the existing knowledge about the pathogenesis of inflammation in CHF and may contribute to the development of new methods and approaches to the treatment of the disease.

Ratios between the Levels of IL-18, Free IL-18, and IL-1ß-Binding Protein Depending on the Severity and Outcome of COVID-19.

In 89 patients with COVID-19, the ratios between IL-18, free IL-18, and IL-18-binding protein (IL-18BP) were analyzed depending on severity and outcome of the disease. At admission to the hospital, the levels of IL-18 and free IL-18 were significantly higher than 3 months after discharge from the hospital, the levels IL-18BP of being almost the same. In patients with more severe lung injury (computed tomography data), the levels of IL-18 and free IL-18 were higher and IL-18BP levels were lower than in patients with mild and moderate COVID-19. Three months after discharge from the hospital, no differences between these parameters were found. In 9 patients who died in the hospital, free IL-18 levels were significantly higher and IL-18BP levels were lower than in survivors. Thus, high levels of bioactive free IL-18 in combination with low levels of IL-18BP can be indicative of severe inflammatory phase of COVID-19 and the risk of worse clinical outcomes.

Dynamics of Soluble Forms of the Immune Checkpoint Components PD-1/PD-L1/B7-H3, CD314/ULBP1, and HLA-G in Peripheral Blood of Melanoma Patients Receiving Blockers of Programmed Cell Death Protein PD-1.

The content of the soluble forms of immune checkpoint components sPD-1, sPD-L1 in blood serum, and sB7-H3, sCD314, sULBP1, sHLA-G in blood plasma of 30 melanoma patients receiving immunotherapy with anti-PD-1 antibodies (nivolumab, pembrolisumab) was measured before and in 4 and 8 weeks after the start of immunotherapy. The control group comprised 70 practically healthy donors. Standard immunoassay kits were used. In melanoma patients, the levels of sPD-L1 and sB7-H3 were significantly higher than in the control group (p<0001), sPD-1 level did not differ from the control, while sCD314 and sHLA-G levels were insignificantly decreased. During therapy, opposite changes in the levels of markers in individual patients were observed, and frequently after the initial increase (or decrease) after the first 4 weeks normalization did occur in the further 4 weeks. No statistically significant associations between the initial levels of markers and direction of their changes during treatment were found, but some trends indicating to the potential benefits from assessment of soluble forms of immune checkpoint proteins for evaluation and monitoring of the efficiency of the therapy with immune checkpoint blockers were revealed: significant decrease of sB7-H3 and sPD-1 levels in the course of treatment, higher initial sPD-1 level in patients with future progression than in those with stabilization or partial effect, and lower progression frequency in patients with increasing sPD-1 and sPD-L1 levels than in those with decreasing markers levels.

Dynamics of the Levels of Interleukin 6, Its Soluble Receptor, and Soluble Glycoprotein 130 in Patients with Chronic Heart Failure and Preserved or Reduced Ejection Fraction.

The features of IL-6 trans-signaling were studied in patients with heart failure with reduced (n=74) and preserved (n=31) ejection fraction (EF) during acute decompensation of HF (ADHF) and after 1 year. Patients with ADHF with reduced EF demonstrated higher levels of IL-6 and soluble glycoprotein 130 in comparison with those in patients with preserved EF: 10.18 (7.07; 16.14) pg/ml vs 6.35 (3.52; 11.00) pg/ml and 543.46 (455.37; 634.43) ng/ml vs 498.50 (408.16; 632.23) ng/ml, respectively. The levels of soluble IL-6 receptor little differed in these groups: 57.82 (47.55; 79.85) ng/ml vs 61.30 (44.97; 78.08) ng/ml. After 1 year, the levels of IL-6 in HF patients with reduced EF significantly decreased (5.36 (3.35; 8.35) pg/ml), while in patients with preserved EF, the decrease in this parameter was less pronounced (5.86 (4.05; 7.32) pg/ml), and the difference between groups disappeared. The levels of soluble glycoprotein 130 increased in both groups: 448.06 (357.74; 550.67) ng/ml vs 385.35 (344.29; 523.72) ng/ml. It should be noted that after 1 year (in stable patients), the levels of soluble IL-6 receptor increased in both groups: 65.75 (54.84; 75.39) ng/ml vs 70.81 (57.51; 82.25) ng/ml. Thus, despite the high levels of IL-6 in HF patients with reduced EF, the potential limiting IL-6 trans-signaling in these patients is higher than in patients with preserved EF.

Reduced Expression of Extracellular Matrix Proteins in the Heart and Kidneys of Rats with Endotoxemia under the Effect of Actinonin.

We studied modulation of the expression of extracellular matrix proteins under conditions of meprin inhibition in rats with LPS-induced endotoxemia. Endotoxemia increased the expression of type I, III, IV collagens and fibronectin in the renal tissue and type III and IV collagens in the heart. Meprin inhibitor actinonin reduced expression of both meprins and genes of extracellular matrix proteins, but the intensity of this effect in the heart and kidney was different. Inhibition of meprins in endotoxemia can prevent pathological remodeling of the extracellular matrix in the heart and kidney.

[Pro-inflammatory cytokines in chronic cardiac failure: state of problem].

Systemic inflammation is characterized by the induction of pro-inflammatory cytokines, the increased level of which in the blood of patients with chronic heart failure (CHF) correlates with unfavorable clinical outcomes. However, it is unclear whether pro-inflammatory cytokines are the cause or the consequence of the disease progression. CHF with preserved ejection fraction and CHF with reduced ejection fraction demonstrate different inflammatory features, which suggests different degrees of pro-inflammatory pathway activation. The review deals with participation of pro-inflammatory cytokines in pathophysiological processes of CHF development, emphasizing the role of interleukin-6 activation and the effects of accompanying diseases on the course of systemic inflammation. The search for new approaches to prevention and therapy of CHF remains actual. The review presents the results of clinical trials of targeted anti-cytokine therapy which have revealed difficulties in controlling inflammation under the conditions of CHF. Identification of specific pro-inflammatory pathways in CHF pathogenesis will allow one to control inflammatory cascades, thus providing a prospective therapeutic strategy.

Compounds of IL-6 Receptor Complex during Acute Lung Injury.

Soluble receptor of IL-6 (sIL-6R) and antagonist of the receptor complex, soluble glycoprotein 130 (sgp130) mediate opposite effects during inflammation. We measured the levels of these cytokines and their ratio in rat blood on the model of acute lung injury. The injury was modeled by the intratracheal administration of LPS. The levels of sgp130 and sIL-6R increased during the inflammatory process in the injured lungs. The sgp130/sIL-6R ratio increased or decreased depending on the intensity of the inflammatory process. sgp130/sIL-6R ratio might reflect the intensity of inflammation during lung injury.

Secretory phospholipase A2 activity in blood serum: the challenge to sense.

Excess levels of secretory phospholipase A2 (sPLA2) is known to contribute to several inflammatory diseases including vascular inflammation correlating with coronary events in coronary artery disease. Thus a method to monitor sPLA2 activity in blood serum is urgently needed. Such method is still a challenge since existing fluorescent probes do not allow to monitor sPLA2 activity directly in blood serum. Here we analyze and overcome barriers in sPLA2 sensing methodology and report a fluorescent probe and a kinetic model of its hydrolysis by sPLA2. New probe is designed with a fluorophore and a quencher not interfering binding to the enzyme. At the same time phospholipid matrix bearing the probe promotes efficient initial quenching of the fluorophore. Kinetic model of probe hydrolysis takes into account signal change due to the side processes. The probe and the kinetic model applied together prove the concept that the activity of sPLA can be measured directly in blood serum.

Effects of LDL lipids on activity of group IIA secretory phospholipase A2.

Effects of phosphatidylcholine, oxidized phosphatidylcholine, sphyngomyelin, cholesterol, and cholesterol esters incorporated in LDL on activity of group IIA secretory phospholipase A2 from human cardiac myxoma were studied. Liposomes containing radioisotope-labeled phosphatidylethanolamine served as the substrate for group IIA secretory phospholipase A2. Oxidized phosphatidylcholine significantly stimulated activity of group IIA secretory phospholipase A2, while phosphatidylcholine in the same concentrations did not modify enzyme activity. Sphyngomyelin incorporated in LDL inhibited group IIA secretory phospholipase A2 activity. Cholesterol and cholesterol esters virtually did not modify enzyme activity. The results indicate that LDL phospholipids and their oxidized forms can be involved in regulation of group IIA secretory phospholipase A2. Study of the mechanisms regulating the proinflammatory group IIA secretory phospholipase A2 can promote the development of new approaches to the diagnosis and treatment of inflammatory processes.

[The effect of LDL on the activity of proinflammatory secretory phospholipase A2 (IIA) depends on the degree of their oxidation].

Phospholipase A2 group IIA which is secreted in inflammation [secPLA2(IIA)] does not always exhibit catalytic activity, although being present in patients' serum. The mechanisms regulating the enzyme activity in peripheral blood have not been studied in sufficient detail. In this study we examined the effects of native and oxidized LDL with varied degree of oxidation on secPLA2(IIA) from human heart myxoma. The degree of LDL oxidation was evaluated from the amount of conjugated dienes and lysophosphatidylcholine. Liposomes containing radio-labelled phosphatidylcholine were used as a substrate in the secPLA2(IIA) activity assay. Native LDL isolated from serum of healthy subjects inhibited secPLA2(IIA) in a dose-dependent manner. Minimally and moderately oxidized LDL in which < 40 % phosphatidylcholine was hydrolysed to lysophosphatidylcholine activated secPL2(IIA). Strongly oxidized LDL in which > 40 % phosphatidylcholine was hydrolysed to lysophosphatidylcholine inhibited the enzyme. Thus, our findings indicate that the characteristics of circulating lipoproteins are changed by their oxidation. Minimal and moderate oxidation of LDL results in activation of secPLA2(IIA), while strong oxidation causes inhibition of the enzyme. Since inflammation leads to an increase in secPLA2(IIA) secretion and LDL oxidation, the results obtained can be used for the diagnostics of inflammatory processes and provide more insight into molecular mechanisms underlying the development of atherosclerosis.

[Effect of atorvastatin therapy on the level of secretory phospholipase A2 group IIA and on the modification of low density lipoproteins in patients with ischemic heart disease].

We studied effect of atorvastatin on secretory phospholipase A2 group IIA (sPLA2-IIA) in blood serum of patients with ischemic heart disease (IHD), lipid composition of low density lipoproteins (LDL) and process of modification of LDL induced by sPLA2-IIA in 20 patients taking 20 mg/day of atorvastatin for 3 months. In patients with initially high level of sPLA2-IIA ( > 8 mcg/l) its concentration significantly decreased. Amount of total cholesterol, triglyceride, lecithin, and lysolecithin remained unchanged, however in equimolar relations there occurred decrease of amount of total cholesterol and increase of cholesterol esters. At incubation of LDL, extracted from patient s plasma before initiation of the study, with human sPLA2-IIA from cardiac myxoma, 3.5 nmol of lysolecithin per 1 mg of LDL protein was formed while at incubation of LDL of same patients, extracted after 3 months of atorvastatin administration, amount of lysolecithin was 1.54 nmol/mg LDL protein. Thus atorvastatin therapy causes lowering of sPLA2-IIA in patients with initially high blood level of the enzyme and to a great extent precludes sPLA2-IIA induced LDL modification.

Effect of serum from cardiovascular patients on catalytic activity of secretory phospholipase A2 (IIA).

Incubation of patients' serum catalytically active by type IIA secretory phospholipase A2 (SP-IIA) with serum containing the enzyme in a high concentration but exhibiting no catalytic activity in 1:1 volume ratio led to a significant inhibition of SP-IIA catalytic activity. donor and patient sera with low levels of SP-IIA had no effect on the serum with SP-IIA activity under these conditions. However, the increase in the content of patients' serum with a low level of SP-IIA in the incubation mixture to 1:2 (v/v) and of donor serum to 1:3 (v/v) also led to blockade of SP-IIA catalytic activity. These results indicate that human serum contains an SP-IIA inhibitor and its concentration decreases significantly in sera with SP-IIA activity.

[Clinico-neurophysiologic and experimental study of the peculiarities of adamantan-sulphate treatment in Parkinson's disease]. / Kliniko-neirofiziologicheskoe i éksperimental'noe izuchenie osobennostei primeneniia sul'fata adamantana pri bolezni Parkinsona.

An experimental investigation of parkinsonism in rats and patients with initial forms of Parkinson's disease was performed by using methods of electromyography and electroneuromyography. Neurophysiologic peculiarities of reorganization of peripheral neuromotor apparatus and criteria for treatment efficacy were detected. The results obtained in the study allowed evaluating of an adequacy of adamantan-sulphate therapy either in the animal experiments and in patients with Parkinson's disease.

[Comparative study of neurophysiological effects of adamantane derivatives in the experimental parkinsonism model]. / Sravnitel'noe izuchenie neirofiziologicheskikh éffektov gruppy aminoadamantana na éksperimental'noi modeli parkinsonizma.

The activity of the adamantane derivative PK-Merz and the new aminoadamantane derivative hemantane was studied by methods of electromyography and electroneuromyography in rats with a model of Parkinson syndrome induced by the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). The toxin produced an increase in the pulse conduction velocity (PCV) in the motor fibers of peripheral nerves and a decrease in the amplitude and frequency of the maximum muscle stress curve. A singe administration of both PK-Merz and hemantane produced unidirectional changes in the neuromyographic parameters and reduced the PCV down to a level in the control group. These results give ground for the clinical investigation of hemantane.

[Serum level of secretory phospholipase A2 (sPLA2) as a predictor of restenosis after coronary angioplasty]. / Uroven' sekretornoi fosfolipazy A2 v syvorotke krovi kak prediktor restenoza posle koronarnoi angioplastiki.

AIM: To elucidate whether secretory phospholipase A2 (sPLA2) level in the blood and catalytic activity are significant predictors of restenosis after coronary angioplasty (CAP). MATERIAL AND METHODS: Samples of venous blood were obtained from 24 patients before CAP and 1, 3, 6 days and 6 months after it. sPLA2 was measured with enzyme immunoassay, catalytic activity--using aqueous emulsion of 14C-labelled phosphatidylcholine. Control coronarography was performed in all the examinees 6 months after CAP. RESULTS: Restenosis was detected in 13 patients. In the serum of their blood sPLA2 rose significantly after CAP and persisted for 6 days after it. If restenosis was not registered, this rise was insignificant and disappeared by day 6 after CAP. Catalytic activity of sPLA2 on day 6 after CAP was significantly higher in patients who later developed restenosis. CONCLUSION: Elevated concentrations of sPLA2 in blood serum of patients after CAP may predict restenosis. Moreover, sPLA2 may not only mark inflammation but directly participate in development of restenosis.

[Reasons causing a lag period in the oxidative phosphorylation process. Isn't ATP an internal uncoupler of ATP synthetase?]. / Prichiny, vyzyvaiushchie poiavlenie lag-perioda v reaktsii okislitel'nogo fosforilirovaniia. Ne iavliaetsia li ATF vnutrennim razobshchitelem ATFsintazy?

The kinetics of oxidative phosphorylation catalyzed by bovine heart submitochondrial particles was studied in a range of MgATP and MgADP concentrations from 0.3 to 10 mM. It is shown that, at a low uncoupler concentration (0.9 microM of tetrachlorotrifluoromethylbenzimidazole, the lag period of the reaction increases from 12 s to 2-3 min, and KM for Pi increases severalfold; the value of Vmax remains practically unchanged. Increasing the [MgATP]/[MgADP] concentration ratio, with their total concentration being unchanged, leads to similar changes in the kinetics of oxidative phosphorylation. The value of delta pH generated on the membrane of AS particles at delta microH+ = 60 delta pH was measured using 9-aminoacridine. It was found that the electrochemical potential of H+ ions shows the same thermodynamic shift in the reaction of energy-dependent Pi -ATP exchange throughout the [MgATP]/[MgADP] concentration range studied, from 0.1 to 10: the synthesis on the ATP molecule is provided by the transmembrane transfer of two H+ ions. It was shown that the binding of ATP and/or ADP in the allosteric site, whose saturation is necessary for the functioning of ATP synthase, occurs with equal constants, 1-2 mM. It is concluded that the lag period in the synthesis of ATP indicates the monomolecular transition ATP hydrolase-->ATP sysnthase, which comes about by the action of transmembrane potential. The binding of MgADP or MgATP renders the enzyme structure "more coupled" or "less coupled", respectively. Structural distinctions manifest themselves in a kinetically different behavior of mitochondrial ATP synthase at [MgATP] > [MgADP] and [MgATP] < [MgADP] and do not suggest futile leakage of H+ through the membrane.