The Relationship between COVID-19 Severity in Children and Immunoregulatory Gene Polymorphism

Coronavirus disease (COVID-19) and its outcomes remain one of the most challenging problems today. COVID-19 in children could be asymptomatic, but can result in a fatal outcome; therefore, predictions of the disease severity are important. The goal was to investigate the human genetic factors that could be associated with COVID-19 severity in children. Single-nucleotide polymorphisms of the following genes were studied: ACE2 (rs2074192), IFNAR2 (rs2236757), TYK2 (rs2304256), OAS1 (rs10774671), OAS3 (rs10735079), CD40 (rs4813003), FCGR2A (rs1801274) and CASP3 (rs113420705). In the case-control study were 30 children with mild or moderate course of the disease; 30 with severe COVID-19 symptoms and multisystem inflammatory syndrome in children (MIS-C) and 15 who were healthy, and who did not have SARS-CoV-2 (PCR negative, Ig G negative). The study revealed that ACE2 rs2074192 (allele T), IFNAR2 rs2236757 (allele A), OAS1 rs10774671 (allele A), CD40 rs4813003 (allele C), CASP3 rs113420705 (allele C) and male sex contribute to severe COVID-19 course and MIS-C in 85.6% of cases. The World Health Organization reported that new SARS-CoV-2 variants may cause previously unseen symptoms in children. Although the study has limitations due to cohort size, the findings can help provide a better understanding of SARS-CoV-2 infection and proactive pediatric patient management.

Blood ACE2 Protein Level Correlates with COVID-19 Severity

ACE2's impact on the severity of COVID-19 is widely discussed but still controversial. To estimate its role in aspects of the main risk factors and comorbidities, we involved post-COVID-19 patients in Ternopil region (Ukraine). The recruitment period was from July 2020 to December 2021. Medical records, treatment modalities, and outcomes were recorded and analyzed. The serum human ACE2 protein was measured with Cusabio ELISA kits (Houston, TX, USA). Statistical analysis was performed with SPSS21.0 software (SPSS Inc., Chicago, IL, USA). The level of the ACE2 serum protein was significantly higher (p < 0.001) in patients with mild symptoms compared to a more severe course of the disease, and inversely had changed from 1 to 90 days after recovery. In patients with mild COVID-19, ACE2 levels significantly decreased over time, while among critical patients, it increased by 34.1 percent. Such results could be explained by ACE2 shedding from tissues into circulation. Loss of the membrane-bound form of the enzyme decreases the virus' entry into cells. Our studies did not identify a sex-related ACE2 serum level correlation. The most common comorbidities were hypertension, cardiovascular diseases, respiratory diseases, and diabetes mellitus. All abovementioned comorbidities except respiratory diseases contribute to the severity of the disease and correlate with ACE2 blood serum levels.

Vessel-on-a-Chip: A Powerful Tool for Investigating Endothelial COVID-19 Fingerprints

Coronavirus disease (COVID-19) causes various vascular and blood-related reactions, including exacerbated responses. The role of endothelial cells in this acute response is remarkable and may remain important beyond the acute phase. As we move into a post-COVID-19 era (where most people have been or will be infected by the SARS-CoV-2 virus), it is crucial to define the vascular consequences of COVID-19, including the long-term effects on the cardiovascular system. Research is needed to determine whether chronic endothelial dysfunction following COVID-19 could lead to an increased risk of cardiovascular and thrombotic events. Endothelial dysfunction could also serve as a diagnostic and therapeutic target for post-COVID-19. This review covers these topics and examines the potential of emerging vessel-on-a-chip technology to address these needs. Vessel-on-a-chip would allow for the study of COVID-19 pathophysiology in endothelial cells, including the analysis of SARS-CoV-2 interactions with endothelial function, leukocyte recruitment, and platelet activation. "Personalization" could be implemented in the models through induced pluripotent stem cells, patient-specific characteristics, or genetic modified cells. Adaptation for massive testing under standardized protocols is now possible, so the chips could be incorporated for the personalized follow-up of the disease or its sequalae (long COVID) and for the research of new drugs against COVID-19.

Influence of chronic hyperhomocysteinemia on the features of bone metabolism in the case of lipopolysaccharide-induced periodontitis

BACKGROUND

Periodontal disease is the second most common oral health problem after dental caries. This increasing prevalence makes it not only a health problem, but also a social issue. The pathogenesis of periodontal disease is associated with a number of adverse exogenous and endogenous factors, including hyperhomocysteinemia (HHcy).

OBJECTIVES

This study aimed to determine the features of bone metabolism in rats with lipopolysaccharide (LPS)-induced periodontitis combined with chronic thiolactone HHcy.

MATERIAL AND METHODS

Forty-eight white, non-linear, mature rats were divided into 4 groups: control (n = 12); LPS‑induced periodontitis (n = 12); chronic thiolactone HHcy (n = 12); and periodontitis combined with HHcy (n = 12). The rats were sacrificed the day after the last LPS injection or the day after the last homocysteine (Hcy) thiolactone administration. Bone metabolism was determined based on the activity of alkaline phosphatase (ALP) and acid phosphatase (AP) in blood serum and periodontal homogenate.

RESULTS

A decrease in ALP activity (by 40.1%; р = 0.001) and the mineralization index (MI) (3.5 times; р < 0.001) with an increase in AP activity (2.0 times; р < 0.001) was observed in the periodontal homogenate of rats with LPS‑induced periodontitis. In the case of LPS‑induced periodontitis combined with chronic thiolactone HHcy, more pronounced changes in the activity of phosphatases and in MI were established as compared to rats with LPS‑induced periodontitis only.

CONCLUSIONS

Chronic thiolactone HHcy enhances disturbances in bone metabolism in LPS‑induced periodontitis. The osteotoxic effect of HHcy is associated with the activation of osteoclastogenesis and enhanced bone resorption. However, further research is required on the subject.

Immunoregulatory Intestinal Microbiota and COVID-19 in Patients with Type Two Diabetes: A Double-Edged Sword

Coronavirus disease 2019, or COVID-19, is a major challenge facing scientists worldwide. Alongside the lungs, the system of organs comprising the GI tract is commonly targeted by COVID-19. The dysbiotic modulations in the intestine influence the disease severity, potentially due to the ability of the intestinal microbiota to modulate T lymphocyte functions, i.e., to suppress or activate T cell subpopulations. The interplay between the lungs and intestinal microbiota is named the gut-lung axis. One of the most usual comorbidities in COVID-19 patients is type 2 diabetes, which induces changes in intestinal microbiota, resulting in a pro-inflammatory immune response, and consequently, a more severe course of COVID-19. However, changes in the microbiota in this comorbid pathology remain unclear. Metformin is used as a medication to treat type 2 diabetes. The use of the type 2 diabetes drug metformin is a promising treatment for this comorbidity because, in addition to its hypoglycemic action, it can increase amount of intestinal bacteria that induce regulatory T cell response. This dual activity of metformin can reduce lung damage and improve the course of the COVID-19 disease.

MICROSCOPIC CHANGES OF THE KIDNEY IN EXPERIMENTAL HYPERHOMOCYSTEINEMIA ON THE BACKGROUND OF HYPER- AND HYPOTHYROIDISM

Hyper- and hypothyroidism are two typical clinical conditions that can cause a variety of metabolic changes, including impaired sulfur-containing amino acids metabolism, increased risk of cardiovascular disease, renal dysfunction, and renal failure. Hypothyroidism has been shown to be associated with increased serum creatinine, decreased glomerular filtration rate, and an increased risk of chronic kidney disease. At the same time, the pathophysiological mechanisms of renal dysfunction induced by excessive iodothyronine secretion are poorly understood. The aim of the study was to establish the reorganization of the kidney structural components under the conditions of experimental hyperhomocysteinemia (HHCy), hyper- and hypothyroidism and their combined effects. Thiolactone HHCy was simulated by administering to animals exogenous homocysteine ​​(HC) in the form of thiolactone at a dose of 100 mg/kg body weight once a day for 28 days. Hyperthyroidism was simulated by daily administration of L-thyroxine at a dose of 200 μg/kg on 21st day, hypothyroidism - daily administration of mercazolyl at a dose of 10 mg/kg on 21st day. Separate groups of animals were administered L-thyroxine and mercazolyl in parallel with HC. A significant degree of dystrophic changes in the structural components of the kidneys under conditions of simulated hyperthyroidism and HHCy was established. Signs of vascular insufficiency in the kidneys were detected. Deformation of renal corpuscles, single focal thickenings and destruction of the outer layer of the renal corpuscle capsule were observed, there was a narrowing of the urinary space in the capsule. Microscopic study of the kidneys of animals under the combined effects of hypothyroidism and HHCy revealed the most significant destructive-degenerative changes in the filtration and reabsorption apparatus of the organ on the background of significant vascular disorders. An increase in number of glomeruli and a decrease of the urinary space of the Shumlyansky-Bowman's capsule were observed in the renal corpuscles. Podocytes underwent significant destructive changes. Damage to the epithelium in the system of tubules was manifested by cell hypertrophy. Under the conditions of simulated HHCy, hyper- and hypothyroidism, and especially with their combined effect, there are significant disorders of the vascular bed with remodeling of the vascular wall. On the background of hemodynamic disorders, there are significant destructive and dystrophic changes in the epitheliocytes of the renal corpuscles of the Shumlyansky-Bowman's capsule, the proximal and distal tubules of the nephron, the filtration and reabsorption apparatus of the nephrons of the organ.

Chitosan self-assembled polymeric nanoparticles for percutaneous delivery of betamethasone in contact dermatitis

OBJECTIVE

The study was performed with an aim to investigate the efficiency of two treatment options in experimental nickel-induced contact dermatitis (CT), with either betamethasone or chitosan cross-linked nano-encapsulated betamethasone lanoline solutions (nano-betamethasone).

METHODS

Male Wistar rats were used. The differences were compared based on lesion visual appearance, skinfold thickness, white blood cell count (WBC), erythrocyte sedimentation rate (ESR), blood serum prooxidant-antioxidant balance (thiobarbituric acid reactive substances, TBARS; supersoxide dismutase, SOD; catalase, KAT), blood cytokine profile (TNF-α, IL-1β, IL-10, and IL-4), and histological examination of affected skin.

RESULTS

All animals treated with nickel sulfate developed CT and systemic inflammatory response on day 12, which only slightly lessened, if left untreated, on day 20. The therapeutic effectiveness of nano-betamethasone was significantly far superior (p < 0.01) compared to betamethasone. Specifically, the visual appearance of lesion severity of betamethasone vs. nano-betamethasone ± SD was 1.82 ± 0.18 vs. 1.17 ± 0.24 points, skinfold thickness-2.68 ± 0.12 vs. 2.12 ± 0.10 mm, ESR-6.38 ± 0.27 vs. 5.12 ± 0.20 mm/h, WBC-8.47 ± 0.28 vs. 7.17 ± 0.24 10⁹/L, TBARS-1.09 ± 0.04 vs. 0.94 ± 0.02 µmol/L, SOD-3.38 ± 0.26 vs. 4.12 ± 0.18 r.u./L, KAT-11.54 ± 0.14 vs. 10.02 ± 0.19 mkatal/L, respectively. The nano-betamethasone formulation was also more effective (p < 0.01) in increasing anti-inflammatory cytokines level, IL-10 (8.96 ± 0.32 vs. 7.54 ± 0.52 pg/mL) and IL-4 (13.16 ± 0.45 vs. 11.43 ± 0.58 pg/mL); and decreasing in pro-inflammatory TNF-α (20.94 ± 2.30 vs. 26.98 ± 1.16 pg/mL) and IL-1β (19.35 ± 1.28 vs. 24.77 ± 1.75 pg/mL), respectively. These findings were also supported with histological examination.

CONCLUSIONS

Nano-betamethasone may be considered as a more successful transcutaneous therapy for managing contact dermatitis compared to ointments consisting of betamethasone in traditional form.

Does thyroid dysfunction influence inflammatory mediators in experimental periodontitis?

Objective. The aim of the present study was to investigate the presence of inflammatory mediators in rats with only periodontitis and periodontitis in a setting of hyper- and hypo-thyroidism and to analyze the correlative linkages between inflammatory mediators and thyroid hormones. Methods. White male 12-14 weeks old inbred rats (n=48) weighing 180-200 g were employed in the experiment. They were randomly divided into the following groups: Group I - control group, Group II - group with a model of periodontitis, Group III - group with a periodontitis in a setting of hyperthyroidism, and Group IV - group with periodontitis in a setting of hypothyroidism. The presence of tumor-necrosis factor-α (TNF-α) and interleukins IL-1β and IL-10 in the periodontal homogenate supernatant was studied by a solid-phase enzyme-linked immunosorbent assay. Results. It was shown that experimental lipopolysaccharide (LPS)-induced periodontitis is accompanied by hyperproduction of pro-inflammatory cytokines (TNF-α, IL-1β) and reduction of anti-inflammatory cytokines (IL-10), whereas TNF-α underwent to maximum changes. Thyroid dysfunction exacerbates cytokine imbalance and severity of inflammation in experimental LPS-induced periodontitis, especially pronounced at hyperthyroidism, as evidenced by the predominance of TNF-α and IL-1β levels in the periodontal homogenate supernatant by 38.5% (р<0.01) and 75.6% (p<0.001), respectively, hyperthyroid over the euthyroid, and by 20.1% (p<0.05) and 24.1% (p<0.05), respectively, over the hypothyroid rats. Conclusions. Thyroid dysfunction, especially hyperthyroidism, may play an important role in the pro-inflammatory response in periodontitis. Hyperproduction of inflammatory mediators in thyroid dysfunction can induce a noticeable damage in the whole apparatus of the periodontium, thereby causing progression of periodontitis.

Transfer efficacy of Escherichia coli O157:H7 between surfaces of green mature tomatoes and common food processing materials

The objectives of this study were: a) to evaluate E. coli O157:H7 survival on green mature tomatoes and squares of common food processing materials – stainless steel, plastic (HDPE), and vinyl conveyor belt (PVC) – post-drying, stored at 25 ºC in the humidified environment for four days; b) to determine pathogen transfer rates (wet, 90 minutes, or 24-hours drying post-inoculation), from inoculated tomato surfaces to uninoculated steel, plastic, and vinyl conveyor belt squares and conversely. It was shown that E. coli O157:H7 did not survive well on the surface of tomatoes, resulting in a decline from 5.3 log10 CFU.mL-1 90 minutes post-drying to 1.4 log10 CFU.mL-1 on day 4. Similarly, the pathogen did not survive well on the surface of food processing squares, with numbers declining over 4 days from 4.04, 4.44, and 4.19 CFU.mL-1 of rinsate 90 minutes squares post-drying to 0.72, 0.50, 0.83  log10 CFU.mL-1, which is close to the detection limit, for the steel, vinyl belt, and plastic, respectively. Successful cross-contamination between tomatoes and food processing surfaces was achieved during wet transfer; while transfer after 90 minutes inoculum post-drying and 24 hours were less successful. This can be explained by both lack of liquid media with suspended bacteria for transfer and fast pathogen die-off after desiccation. Dry transfers, as shown by the percentage of “positive” for pathogen presence tomatoes and squares, as well as bacterial counts, were more successful from tomatoes to squares, but not conversely. Special concern raised vinyl conveyor belt, where the surface picked up the most pathogen cells from the surface of tomatoes, resulting in 100% positive during 90 minute-dry transfers, followed by plastic (66.7% positive) and steel (55.6% positive). To summarize, we presented data on the possibility of cross-contamination between mature green tomatoes and common food processing surfaces, which may be interesting for the processors for risk evaluation.

A Comparative Study of Connective Tissue Metabolism Indices in Experimental Comorbidity-Free Periodontitis and Periodontitis Combined with Thyroid Dysfunction

Periodontal disease is a chronic bacterial infection characterized by persistent inflammation, connective tissue breakdown, and alveolar bone destruction. The current study aimed to compare the connective tissue metabolism indices in rats with comorbidity-free periodontitis and in animals with periodontitis in a setting of hyper-and hypothyroidism. 12-14-week-old inbred white male rats (n=48) were included in the experiment. They were randomly divided into the following groups: control, animals with a model of periodontitis, animals with periodontitis in a setting of hyperthyroidism, animals with periodontitis in a setting of hypothyroidism. Serum levels of free thyroxine, free triiodothyronine, and thyroid-stimulating hormone were assayed using ELISA kits manufactured by Vector Best (Russia) to confirm the hyper- and hypothyroid status. Collagenolytic activity, the content of glycosaminoglycans, free hydroxyproline, and fucose, unbound with proteins in blood serum were assayed using the spectrophotometric method. We have found the increasing of collagenolytic activity by 46.1% (р<0.001), the content of free hydroxyproline by 74.1% (р<0.001), the content of glycosaminoglycans by 1.8 times (р<0.001), the content of fucose, unbound with proteins by 2.8 times (р<0.001) in rats with periodontitis vs. the control group. The development of periodontitis in a setting of thyroid dysfunction leads to an even more significant increase in the destruction of connective tissue, which is confirmed by a significant increase in the content of studied indices vs. euthyroid animals, both in hyperthyroidism and hypothyroidism.

A comparative study of oral microbiocenosis structure in experimental comorbidity-free periodontitis and in periodontitis combined with thyroid dysfunction

Thyroid hormones regulate numerous metabolic processes. Therefore, any alteration in their synthesis or function has important health implications. However, limited data are available regarding the relationship between thyroid hormone imbalance and periodontal health.

AIM

The aim of the study was to perform a comparative analysis of qualitative and quantitative structure of oral microbiocenosis in rats with comorbidity-free periodontitis and in animals with periodontitis in a setting of hyper- and hypothyroidism.

MATERIALS AND METHODS

Inbred white male rats (n=48) were randomly divided into the following groups: I - control animals, II - animals with a model of periodontitis, III - rats with periodontitis in a setting of hyperthyroidism, IV - rats with periodontitis in a setting of hypothyroidism. Samples for microbiological investigations were taken from dental surfaces (on the border between hard tissue and gums in the interdental spaces). The isolated pure cultures were identified by their morphological, tinctorial, cultural and biochemical properties.

RESULTS

The oral dysbiosis occurring in a setting of periodontitis in rats is chiefly characterized by increased quantity of coccal forms and by increased candidal inoculation; these organisms cumulatively inhibit the growth of normal microbial flora, such as Lactobacilli, bacteroids and Bifidobacteria. The periodontitis in a setting of thyroid dysfunction increases both the species variety and the quantitative counts of oral microbial flora, with predominance of such microbial organisms as Staph. aureus, E. coli, E. faecalis, Candida albicans and P. aeruginosa. Comparative assessment of intensity of oral microbial colonization in hyper- and hypothyroid animals with periodontitis has demonstrated significant changes only for the strains of S. aureus, yeast-like fungi and Candida albicans, which were predominant in hyperthyroid rats.

CONCLUSIONS

Both hyperthyroidism and hypothyroidism exacerbate changes in the qualitative and quantitative structure of oral microbiocenosis in case of experimental periodontitis.

Influence of suspension liquid total solids on E. coli O157:H7 survival and transfer efficacy between green tomatoes and cardboard

The objectives of this study were: a) to determine E. coli O157:H7 survival on tomatoes and cardboard squares post-drying, stored at 25 ºC in humidified environment for four days, in buffered peptone water (BPW), and 0.1% diluted peptone (DP); b) to determine pathogen transfer rates (0, 1.5, or 24-hours drying post-inoculation), from inoculated tomato surfaces to uninoculated cardboard squares and conversely; and c) to evaluate SystemSure Plus ATP luminometer for recognizing contamination on visibly soiled (BPW) or visible clean (DP) cardboard. In tomato inoculation studies, E. coli O157:H7 survived better on the fruit when the inoculum was prepared using DP as compared to BPW. The 1.5-hours post drying counts of 5.34 and 5.76 log10 CFU.mL-1 in the rinsate substantially declined to 1.45 and 1.17 log10 CFU.mL-1 on day four, for DP and BPW, respectively. In cardboard inoculation studies, E. coli O157:H7 persisted for four days, with 1.5-hours post-drying counts and day four counts of 4.53 (DP) and 2.55 log10 CFU.mL-1 (BPW), contrary to 3.81 (DP) and 1.92 log10 CFU.mL-1 (BPW). Under the first impression, the slower die-off of E. coli O157:H7 on cardboard questions the possibility of reusing cardboard boxes due to the potential for cross-contamination. In wet transfer (0 hour drying) trials, both tomato-to-cardboard and cardboard-to-tomato yielded 100% positive transfers irrespective of diluent type. Dry transfer (1.5-hours drying interval post inoculation) from tomato-to-cardboard were 100% positive, but no positives were noted when inoculated, dried cardboard was contacted to tomatoes, irrespective of diluent. Results of transfers with BPW as the diluent showed 100% positive transfer from 24-hours dry tomatoes-to-cardboard, as inoculation spots on the tomatoes remained moist due to hygroscopic nature of solutes in BPW. Conversely, only a 40% positive transfer rate was observed under the same conditions with DP as diluent. No positive transfers were recorded from 24-hours dry cardboard-to-tomatoes, irrespective of diluent type. Though E. coli O157:H7 survived better on the surface of cardboard compared to the surface of tomatoes on day four, the dry transfers were more efficient from tomatoes-to-cardboard than conversely, possibly due to smooth and hydrophobic properties of the tomato, and rough and porous surface of the cardboard. ATP luciferase UltrasnapTM swab test showed 9/9 “pass” results for sterile liquid DP and BPW, while 9/9 “fail” results were observed with liquid peptone and BPW contaminated at ca. 9.0 log10 CFU.mL-1E. coli O157:H7. Cardboard squares treated and dried, with sterile DP, showed 8/9 “pass” ATP luciferase results, and 1/9 “warning”, while cardboard squares with contaminated DP showed 9/9 “fail” result. Cardboard squares treated and dried, with sterile BPW, showed 7/9 “pass” ATP luciferase results, and 2/9 “warning”, while cardboard squares with contaminated BPW showed 9/9 “fail” result. Luminometer can simplify detection of microbial load, as well as organic residues, helping to check cardboard boxes for cleanness.

CORRELATION BETWEEN CONNECTIVE TISSUE METABOLISM AND THYROID DYSFUNCTION IN RATS WITH PERIODONTITIS

The aim of the study was to clarify mechanisms of the periodontitis development in rats with thyroid dysfunction based on a comparative analysis of the correlations between the connective tissue metabolism indices and the concentration of thyroid stimulating hormone, free thyroxine and free triiodothyronine in blood serum. 12-14-week-old inbred white male rats (n=48) were included to the experiment. They were randomly divided into the following groups: control; animals with a model of periodontitis; animals with periodontitis in a setting of hyperthyroidism; animals with periodontitis in a setting of hypothyroidism. Concentrations of free thyroxine, free triiodothyronine and thyroid stimulating hormone were assayed with ELISA method. Collagenolytic activity, content of glycosaminoglycans, free hydroxyproline, fucose, unbound with proteins were determined by the spectrophotometric method. The linkages between the studied indices were established on the basis of the results of the correlation analysis using the Pearson correlation coefficient. Our research has found different interconnections between the indices of connective tissue metabolism and free triiodothyronine, free thyroxine and thyroid stimulating hormone concentrations in case of experimental periodontitis combined with thyroid dysfunction, indicating that thyroid gland has regulatory influence on connective tissue metabolism. In hypothyroid rats more correlations have been established compared to the hyperthyroid rats.

Microbiological comparison of visibly dirty and visibly clean mature green tomatoes before and after treatments with deionized water or chlorine in model overhead spray brush roller system

The purpose of the current study was to compare natural microflora counts of mature green tomatoes as influenced by visual cleanness, and investigate ability of chlorine sanitizer to reduce different groups of natural microflora on the surface of tomatoes using overhead spray brush roller system. We hypothesized that natural microflora might not be equally affected, with vegetative Gram negative bacteria being more sensitive and soil-related Gram positive sporoforming bacilli and molds more resistant. Microflora from untreated visibly clean and visibly dirty tomatoes, as well as from visibly clean tomatoes after 30 seconds deionized water or 100 ppm chlorine treatments, was recovered and spread plated on Tryptic Soy agar, MacConkey agar, and acidified Potato Dextrose agar. Microflora from untreated and chlorine-treated tomatoes was non-specifically enriched and plated on agar with chlorine paper disc diffusion assay applied to check for inhibition zone differences. Interestingly, there was no significant difference in plate counts between visibly clean and dirty tomatoes (p >0.05). Chlorine was more effective than water alone to reduce microbial counts on tomatoes for all microbiological media tested. Based on similar relative reductions of microorganisms in each group, it was concluded that chlorine may have no preferential kill for investigated groups of microorganisms. High counts remaining after treatment with chlorine solution suggested possibility of resistant microbial biofilm formation on the surface of tomatoes.

INFLUENCE OF CHRONIC HYPERHOMOCYSTEINEMIA ON METABOLISM OF SULFUR CONTAINING AMINO ACIDS IN THE RATS' HEART AND BRAIN ON THE BACKGROUND OF HYPERTHYREOSIS AND HYPOTHYREOSIS

The effect of experimental HHCy on the processes of transsulfuration of sulfur amino acids in the tissues of heart and brain, the levels of HCy, cysteine, H2S in blood serum of experimental animals with hyperthyroidism and hypothyroidism has been studied in the research. The experiment was performed on white male rats with simulated HHCy, hyper- and hypothyroidism, HHCy with different thyroid function. In the heart, the activity of cysteine aminotransferase (CAT), γ-glutamate cysteine ligase (γ-GCL), sulfite oxidase (SO) was determined. In the brain, the activity of cystathionine-β-synthase (CBS), cysteine ​​dioxygenase (CDO), GCL and SO was determined. In serum the total level of HCy, cysteine ​​and H2S was evaluated. HHCy caused inhibition of transsulfuration pathway of cysteine in the brain that was evidenced by decreased activity of CBS and CAT in heart that caused increase in the level of HCy and cysteine ​​as well as decrease in the level of H2S in blood serum. Hyperthyroidism causes increased activity of CBS in brain and of CAT in heart. Hyperthyroidism leads to decrease in the level of HCy in blood serum compare to the control, as well as increase in the level of H2S compare to the group of animals with HHCy. Hypothyroidism causes inhibition of cysteine ​​metabolism, decrease in of HCy and cysteine levels. In cases of HHCy simulated by administration of thiolactone-HCy the activity of CBS and SO in the brain of rats, and CAT in the heart is increased. Hyperthyroidism causes increase of the activity of the CBS, CDO, and SO in the brain, as well as CAT in the heart. At the same time, the simultaneous administration of L-tyroxysin into the animals with HHCy leads to increase in the enzyme activity of CBS, CDO, γ-GCL and SO in the brain of the animals and increase of CAT and γ-GCL in the myocardium. Hypothyroidism in the brain of animals causes a decrease in the activity of the CBS, CAT and SO, and at the same time, the activity of SO only decreases in the myocardium of animals. An increase in the level of HCy and cysteine, a decrease in the level of H2S in the blood of experimental animals during hypothyroidism, as well as inhibition of the transsulfuration enzyme activity in the brain and heart are significant markers of the development of cardiovascular pathologies and mortality associated with hypothyroidism.

Metformin Protects the Heart Against Hypertrophic and Apoptotic Remodeling After Myocardial Infarction

Cardiovascular complications are the most prevalent cause of morbidity and mortality in diabetic patients. Metformin is currently the first-line blood glucose-lowering agent with potential relevance to cardiovascular diseases. However, the underpinning mechanisms of action remain elusive. Here, we report that metformin represses cardiac apoptosis at least in part through inhibition of Forkhead box O1 (FoxO1) pathway. In a mouse model of ischemia-reperfusion (I/R), treatment with metformin attenuated cardiac and hypertrophic remodeling after 14 days of post-reperfusion. Additionally, cardiac expression of brain-like natriuretic peptide (BNP) was significantly reduced in metformin-treated mice after 14 days of cardiac I/R. In cultured H9C2 cells, metformin counteracted hypertrophic and apoptotic responses to metabolic or hypoxic stress. FoxO1 silencing by siRNA abolished anti-apoptotic effect of metformin under hypoxic stress in H9C2 cells. Taken together, these results suggest that metformin protects the heart against hypertrophic and apoptotic remodeling after myocardial infarction.

IMMUNOLOGICAL DISTRESS IN EXPERIMENTAL CRANIAL TRAUMA COMBINED WITH INSULIN DEPENDENT DIABETES (EXPERIMENTAL STUDY)

This article describes the immunological events and investigates important mediators of the inflammatory immune response after experimental cranial trauma combined with type I diabetes. It was shown that the rats with induced diabetes and traumatic brain injury suffered more profound damage to the immune system that was not restored back to the basal level within 14 days. Proinflammatory cytokine concentrations increased, while anti-inflammatory cytokine concentrations decreased by day 14, increasing risk for systemic inflammatory response syndrome and multi-organ failure. Factors responsible for humoral immunity and cell-mediated immunity were consistently lower by day 14, which might make diabetic rats more susceptible to infections compared to rats with brain injury alone.

Leptin-induced endothelial dysfunction in obesity

Hyperleptinemia accompanying obesity affects endothelial nitric oxide (NO) and is a serious factor for vascular disorders. NO, superoxide (O(2)(-)), and peroxynitrite (ONOO(-)) nanosensors were placed near the surface (5+/-2 microm) of a single human umbilical vein endothelial cell (HUVEC) exposed to leptin or aortic endothelium of obese C57BL/6J mice, and concentrations of calcium ionophore (CaI)-stimulated NO, O(2)(-), ONOO(-) were recorded. Endothelial NO synthase (eNOS) expression and L-arginine concentrations in HUVEC and aortic endothelium were measured. Leptin did not directly stimulate NO, O(2)(-), or ONOO(-) release from HUVEC. However, a 12-h exposure of HUVEC to leptin increased eNOS expression and CaI-stimulated NO (625+/-30 vs. 500+/-24 nmol/l control) and dramatically increased cytotoxic O(2)(-) and ONOO(-) levels. The [NO]-to-[ONOO(-)] ratio ([NO]/[ONOO(-)]) decreased from 2.0+/-0.1 in normal to 1.30+/-0.1 in leptin-induced dysfunctional endothelium. In obese mice, a 2.5-fold increase in leptin concentration coincided with 100% increase in eNOS and about 30% decrease in intracellular L-arginine. The increased eNOS expression and a reduced l-arginine content led to eNOS uncoupling, a reduction in bioavailable NO (250+/-10 vs. 420+/-12 nmol/l control), and an elevated concentration of O(2)(-) (240%) and ONOO(-) (70%). L-Arginine and sepiapterin supplementation reversed eNOS uncoupling and partially restored [NO]/[ONOO(-)] balance in obese mice. In obesity, leptin increases eNOS expression and decreases intracellular l-arginine, resulting in eNOS an uncoupling and depletion of endothelial NO and an increase of cytotoxic ONOO(-). Hyperleptinemia triggers an endothelial NO/ONOO(-) imbalance characteristic of dysfunctional endothelium observed in other vascular disorders, i.e., atherosclerosis and diabetes.

Leptin-induced endothelial dysfunction in obesity

Hyperleptinemia accompanying obesity affects endothelial nitric oxide (NO) and is a serious factor for vascular disorders. NO, superoxide (O(2)(-)), and peroxynitrite (ONOO(-)) nanosensors were placed near the surface (5+/-2 microm) of a single human umbilical vein endothelial cell (HUVEC) exposed to leptin or aortic endothelium of obese C57BL/6J mice, and concentrations of calcium ionophore (CaI)-stimulated NO, O(2)(-), ONOO(-) were recorded. Endothelial NO synthase (eNOS) expression and L-arginine concentrations in HUVEC and aortic endothelium were measured. Leptin did not directly stimulate NO, O(2)(-), or ONOO(-) release from HUVEC. However, a 12-h exposure of HUVEC to leptin increased eNOS expression and CaI-stimulated NO (625+/-30 vs. 500+/-24 nmol/l control) and dramatically increased cytotoxic O(2)(-) and ONOO(-) levels. The [NO]-to-[ONOO(-)] ratio ([NO]/[ONOO(-)]) decreased from 2.0+/-0.1 in normal to 1.30+/-0.1 in leptin-induced dysfunctional endothelium. In obese mice, a 2.5-fold increase in leptin concentration coincided with 100% increase in eNOS and about 30% decrease in intracellular L-arginine. The increased eNOS expression and a reduced l-arginine content led to eNOS uncoupling, a reduction in bioavailable NO (250+/-10 vs. 420+/-12 nmol/l control), and an elevated concentration of O(2)(-) (240%) and ONOO(-) (70%). L-Arginine and sepiapterin supplementation reversed eNOS uncoupling and partially restored [NO]/[ONOO(-)] balance in obese mice. In obesity, leptin increases eNOS expression and decreases intracellular l-arginine, resulting in eNOS an uncoupling and depletion of endothelial NO and an increase of cytotoxic ONOO(-). Hyperleptinemia triggers an endothelial NO/ONOO(-) imbalance characteristic of dysfunctional endothelium observed in other vascular disorders, i.e., atherosclerosis and diabetes.

Effect of aspirin on constitutive nitric oxide synthase and the biovailability of NO

INTRODUCTION

Aspirin decreases the activity of iNOS and the formation of prostanoids. Constitutive nitric oxide synthase (cNOS) is present in endothelial cells, platelets, leukocytes and neurons, yet no data are available on the effect of aspirin on cNOS and the bioavailability of NO produced by this enzyme.

MATERIALS AND METHODS

Human umbilical vein endothelial cells (HUVECs), rat adrenal gland pheochromocytoma cells (PC-12) and human platelets were incubated with different aspirin concentrations. The kinetics of NO, O2- and ONOO- release were measured simultaneously in single cells or platelet suspensions using tandem electrochemical nanosensors. The NO, O2- and ONOO- release from cells and platelets was stimulated with calcium ionophore and collagen, respectively. cNOS expression was estimated by Western blot analysis.

RESULTS

Incubation of HUVECs and PC-12 with 10(-5) mol/l of aspirin increased cNOS expression by 70 +/- 7% and 50 +/- 5, respectively. However, the NO concentration increased only by 33% in HUVECs incubated with the same aspirin concentration. Incubation of HUVECs with aspirin also increased the O2- and ONOO- production. Therefore the bioavailability of NO increased only slightly in endothelium and did not reflect the increase in eNOS. This was in contrast to platelets, where maximal NO bioavailability almost doubled after incubation with aspirin.

CONCLUSIONS

Aspirin did not have a significant effect on the NO bioavailability in endothelial cells. However, aspirin highly improved the NO production in platelets. The high NO production in platelets may counteract the effect of thromboxane, inhibit platelet aggregation, and compensate for the reduction of prostacycline concentration by aspirin.

Monoclonal antibodies identify residues 199-216 of the integrin alpha2 vWFA domain as a functionally important region within alpha2beta1

Integrin alpha2beta1 is the major receptor for collagens in the human body, and the collagen-binding site on the alpha2 subunit von Willebrand factor A-type domain (vWFA domain) is now well defined. However, the biologically important conformational changes that are associated with collagen binding, and the means by which the vWFA domain is integrated into the whole integrin are not completely understood. We have raised monoclonal antibodies against recombinant alpha2 vWFA domain for use as probes of function. Three antibodies, JA202, JA215 and JA218, inhibited binding to collagen, collagen I C-propeptide and E-cadherin, demonstrating that their function is important for structurally diverse alpha2beta1 ligands. Cross-blocking studies grouped the epitopes into two clusters: (I) JA202, the inhibitory antibody, Gi9, and a non-inhibitory antibody, JA208; (II) JA215 and JA218. Both clusters were sensitive to events at the collagen binding site, as binding of Gi9, JA202, JA215 and JA218 were inhibited by collagen peptide, JA208 binding was enhanced by collagen peptide, and binding of JA202 was decreased after mutagenesis of the cation-binding residue Thr(221) to alanine. Binding of cluster I antibodies was inhibited by the anti-functional anti-beta1 antibody Mab13, and binding of Gi9 and JA218 to alpha2beta1 was inhibited by substituting Mn(2+) for Mg(2+), demonstrating that these antibodies were sensitive to changes initiated outside the vWFA domain. Mapping of epitopes showed that JA202 and Gi9 bound between residues 212-216, while JA208 bound between residues 199-216. We have therefore identified two epitope clusters with novel properties; i.e. they are intimately associated with the collagen-binding site, responsive to conformational changes at the collagen-binding site and sensitive to events initiated outside the vWFA domain.