In vitro and in vivo toxicity of thiolated and PEGylated organosilica nanoparticles.

This study comprises the comprehensive toxicological assessment of thiolated organosilica nanoparticles (NPs) synthesised from 3-mercaptopropyltrimethoxysilane (MPTS). We investigated the influence of three different types of nanoparticles synthesised from 3-mercaptopropyltrimethoxysilane: the starting thiolated silica (Si-NP-SH) and their derivatives prepared by surface PEGylation with PEG 750 (Si-NP-PEG750) and 5000 Da (Si-NP-PEG5000) on biological subjects from in vitro to in vivo experiments to explore the possible applications of those nanoparticles in biomedical research. As a result of this study, we generated a comprehensive understanding of the toxicological properties of these nanoparticles, including their cytotoxicity in different cell lines, hemolytic properties, in vitro localisation, mucosal irritation properties and biodistribution in BALB/c mice. Our findings indicate that all three types of nanoparticles can be considered safe and have promising prospects for use in biomedical applications. Nanoparticles did not affect the viability of HPF, MCF7, HEK293 and A549 cell lines at low concentrations (up to 100 µg/mL); moreover, they did not cause organ damage to BALB/c mice at concentrations of 10 mg/kg. The outcomes of this study enhance our understanding of the impact of organosilica nanoparticles on health and the environment, which is vital for developing silica nanoparticle-based drug delivery systems and provides opportunities to expand the applications of organosilica nanoparticles.

The Role of Cdc42 in the Insulin and Leptin Pathways Contributing to the Development of Age-Related Obesity.

Age-related obesity significantly increases the risk of chronic diseases such as type 2 diabetes, cardiovascular diseases, hypertension, and certain cancers. The insulin-leptin axis is crucial in understanding metabolic disturbances associated with age-related obesity. Rho GTPase Cdc42 is a member of the Rho family of GTPases that participates in many cellular processes including, but not limited to, regulation of actin cytoskeleton, vesicle trafficking, cell polarity, morphology, proliferation, motility, and migration. Cdc42 functions as an integral part of regulating insulin secretion and aging. Some novel roles for Cdc42 have also been recently identified in maintaining glucose metabolism, where Cdc42 is involved in controlling blood glucose levels in metabolically active tissues, including skeletal muscle, adipose tissue, pancreas, etc., which puts this protein in line with other critical regulators of glucose metabolism. Importantly, Cdc42 plays a vital role in cellular processes associated with the insulin and leptin signaling pathways, which are integral elements involved in obesity development if misregulated. Additionally, a change in Cdc42 activity may affect senescence, thus contributing to disorders associated with aging. This review explores the complex relationships among age-associated obesity, the insulin-leptin axis, and the Cdc42 signaling pathway. This article sheds light on the vast molecular web that supports metabolic dysregulation in aging people. In addition, it also discusses the potential therapeutic implications of the Cdc42 pathway to mitigate obesity since some new data suggest that inhibition of Cdc42 using antidiabetic drugs or antioxidants may promote weight loss in overweight or obese patients.

Circulating adiponectin levels, expression of adiponectin receptors, and methylation of adiponectin gene promoter in relation to Alzheimer's disease.

BACKGROUND: The role of adiponectin (ADIPOQ) in Alzheimer's disease (AD) has been documented, however, demonstrating controversial results. In this study, we investigated blood serum ADIPOQ levels, methylation of the adiponectin gene promoter, and adiponectin receptors (AdipoR1 and AdipoR2) expression in blood samples isolated from AD patients and healthy controls. METHODS: We performed a case-control study including 248 subjects (98 AD patients and 150 healthy controls); ADIPOQ serum levels, AdipoR1, and AdipoR2 levels in PBMC were measured by ELISA Kits, and ADIPOQ gene methylation was analyzed using methyl-specific PCR. RESULTS: Serum adiponectin levels were threefold higher in the AD group compared to the controls. We have also found a positive correlation between adiponectin and MMSE scores and high-density lipoprotein cholesterol (HDL-C) in AD patients. A significant difference in the proportion of methylation of the CpG sites at - 74 nt of the ADIPOQ gene promoter was detected in AD cases, and the levels of adiponectin in blood serum were significantly higher in methylated samples in the AD group compared to controls. The amount of AdipoR1 was significantly higher among AD subjects, while the expression of AdipoR2 did not vary between AD patients and controls. CONCLUSION: These findings may contribute to a deeper understanding of the etiological factors leading to the development of dementia and may serve as a basis for the development of predictive biomarkers of AD.

Study of gut microbiota alterations in Alzheimer's dementia patients from Kazakhstan.

We have investigated the diversity and composition of gut microbiotas isolated from AD (Alzheimer's disease) patients (n = 41) and healthy seniors (n = 43) from Nur-Sultan city (Kazakhstan). The composition of the gut microbiota was characterized by 16S ribosomal RNA sequencing. Our results demonstrated significant differences in bacterial abundance at phylum, class, order, and genus levels in AD patients compared to healthy aged individuals. Relative abundance analysis has revealed increased amount of taxa belonging to Acidobacteriota, Verrucomicrobiota, Planctomycetota and Synergistota phyla in AD patients. Among bacterial genera, microbiotas of AD participants were characterized by a decreased amount of Bifidobacterium, Clostridia bacterium, Castellaniella, Erysipelotrichaceae UCG-003, Roseburia, Tuzzerella, Lactobacillaceae and Monoglobus. Differential abundance analysis determined enriched genera of Christensenellaceae R-7 group, Prevotella, Alloprevotella, Eubacterium coprostanoligenes group, Ruminococcus, Flavobacterium, Ohtaekwangia, Akkermansia, Bacteroides sp. Marseille-P3166 in AD patients, whereas Levilactobacillus, Lactiplantibacillus, Tyzzerella, Eubacterium siraeum group, Monoglobus, Bacteroides, Erysipelotrichaceae UCG-003, Veillonella, Faecalibacterium, Roseburia, Haemophilus were depleted. We have also found correlations between some bacteria taxa and blood serum biochemical parameters. Adiponectin was correlated with Acidimicrobiia, Faecalibacterium, Actinobacteria, Oscillospiraceae, Prevotella and Christensenellaceae R-7. The Christensenellaceae R-7 group and Acidobacteriota were correlated with total bilirubin, while Firmicutes, Acidobacteriales bacterium, Castellaniella alcaligenes, Lachnospiraceae, Christensenellaceae and Klebsiella pneumoniae were correlated with the level of CRP in the blood of AD patients. In addition, we report the correlations found between disease severity and certain fecal bacteria. This is the first reported study demonstrating gut microbiota alterations in AD in the Central Asian region.

Plant Extract of Limonium gmelinii Attenuates Oxidative Responses in Neurons, Astrocytes, and Cerebral Endothelial Cells In Vitro and Improves Motor Functions of Rats after Middle Cerebral Artery Occlusion.

There are numerous publications demonstrating that plant polyphenols can reduce oxidative stress and inflammatory processes in the brain. In the present study we have investigated the neuroprotective effect of plant extract isolated from the roots of L. gmelinii since it contains a rich source of polyphenols and other biologically active compounds. We have applied an oxidative and inflammatory model induced by NMDA, H2O2, and TNF-α in human primary neurons and astrocytes, and mouse cerebral endothelial cell (CECs) line in vitro. The levels of ROS generation, NADPH oxidase activation, P-selectin expression, and activity of ERK1/2 were evaluated by quantitative immunofluorescence analysis, confocal microscopy, and MAPK assay. In vivo, sensorimotor functions in rats with middle cerebral artery occlusion (MCAO) were assessed. In neurons NMDA induced overproduction of ROS, in astrocytes TNF-α initiated ROS generation, NADPH oxidase activation, and phosphorylation of ERK1/2. In CECs, the exposure by TNF-α induced oxidative stress and triggered the accumulation of P-selectin on the surface of the cells. In turn, pre-treatment of the cells with the extract of L. gmelinii suppressed oxidative stress in all cell types and pro-inflammatory responses in astrocytes and CECs. In vivo, the treatment with L. gmelinii extract improved motor activity in rats with MCAO.

Mesenchymal Stem Cells Coated with Synthetic Bone-Targeting Polymers Enhance Osteoporotic Bone Fracture Regeneration.

Osteoporosis is a progressive skeletal disease characterized by reduced bone density leading to bone fragility and an elevated risk of bone fractures. In osteoporotic conditions, decrease in bone density happens due to the augmented osteoclastic activity and the reduced number of osteoblast progenitor cells (mesenchymal stem cells, MSCs). We investigated a new method of cell therapy with membrane-engineered MSCs to restore the osteoblast progenitor pool and to inhibit osteoclastic activity in the fractured osteoporotic bones. The primary active sites of the polymer are the N-hydroxysuccinimide and bisphosphonate groups that allow the polymer to covalently bind to the MSCs' plasma membrane, target hydroxyapatite molecules on the bone surface and inhibit osteolysis. The therapeutic utility of the membrane-engineered MSCs was investigated in female rats with induced estrogen-dependent osteoporosis and ulnar fractures. The analysis of the bone density dynamics showed a 27.4% and 21.5% increase in bone density at 4 and 24 weeks after the osteotomy of the ulna in animals that received four transplantations of polymer-modified MSCs. The results of the intravital observations were confirmed by the post-mortem analysis of histological slices of the fracture zones. Therefore, this combined approach that involves polymer and cell transplantation shows promise and warrants further bio-safety and clinical exploration.

Improvement of Neurological Function in Rats with Ischemic Stroke by Adipose-derived Pericytes.

Pericytes possess high multipotent features and cell plasticity, and produce angiogenic and neurotrophic factors that indicate their high regenerative potential. The aim of this study was to investigate whether transplantation of adipose-derived pericytes can improve functional recovery and neurovascular plasticity after ischemic stroke in rats. Rat adipose-derived pericytes were isolated from subcutaneous adipose tissue by fluorescence-activated cell sorting. Adult male Wistar rats were subjected to 90 min of middle cerebral artery occlusion followed by intravenous injection of rat adipose-derived pericytes 24 h later. Functional recovery evaluations were performed at 1, 7, 14, and 28 days after injection of rat adipose-derived pericytes. Angiogenesis and neurogenesis were examined in rat brains using immunohistochemistry. It was observed that intravenous injection of adipose-derived pericytes significantly improved recovery of neurological function in rats with stroke compared to phosphate-buffered saline-treated controls. Immunohistochemical analysis revealed that the number of blood capillaries was significantly increased along the ischemic boundary zone of the cortex and striatum in stroke rats treated with adipose-derived pericytes. In addition, treatment with adipose-derived pericytes increased the number of doublecortin positive neuroblasts. Our data suggest that transplantation of adipose-derived pericytes can significantly improve the neurologic status and contribute to neurovascular remodeling in rats after ischemic stroke. These data provide a new insight for future cell therapies that aim to treat ischemic stroke patients.

The Links Between the Gut Microbiome, Aging, Modern Lifestyle and Alzheimer's Disease.

Gut microbiome is a community of microorganisms in the gastrointestinal tract. These bacteria have a tremendous impact on the human physiology in healthy individuals and during an illness. Intestinal microbiome can influence one's health either directly by secreting biologically active substances such as vitamins, essential amino acids, lipids et cetera or indirectly by modulating metabolic processes and the immune system. In recent years considerable information has been accumulated on the relationship between gut microbiome and brain functions. Moreover, significant quantitative and qualitative changes of gut microbiome have been reported in patients with Alzheimer's disease. On the other hand, gut microbiome is highly sensitive to negative external lifestyle aspects, such as diet, sleep deprivation, circadian rhythm disturbance, chronic noise, and sedentary behavior, which are also considered as important risk factors for the development of sporadic Alzheimer's disease. In this regard, this review is focused on analyzing the links between gut microbiome, modern lifestyle, aging, and Alzheimer's disease.

Elevated levels of the small GTPase Cdc42 induces senescence in male rat mesenchymal stem cells.

Mesenchymal stem cells (MSCs) represent a promising cell source for cellular therapy and tissue engineering and are currently being tested in a number of clinical trials for various diseases. However, like other somatic cells, MSCs age, and this senescence is accompanied by a progressive decline in stem cell function. Several lines of evidence suggest a role for the Rho family GTPase Cdc42 activity in cellular senescence processes. In the present study, we have examined aging-associated Cdc42 activity in rat adipose-derived mesenchymal stem cells (ADMSCs) and the consequences of pharmacological inhibition of Cdc42 in ADMSCs from aged rats. We demonstrate that ADMSCs show a decreased rate of cell growth and a decreased ability to differentiate into chrodrogenic, osteogenic and adipogenic cell lineages as a function of rat age. This is accompanied with an increased staining for SA-ß-Gal activity and increased levels of Cdc42 bound to GTP. Treatment of ADMSCs from 24-month old rats with three Cdc42 inhibitors significantly increased proliferation rates, decreased SA-ß-Gal staining, and reduced Cdc42-GTP. The Cdc42 inhibitor CASIN increased adipogenic and osteogenic differentiation potential in ADMSCs from 24-month old rats, and decreased the levels of radical oxygen species (ROS), p16INK4a levels, F-actin, and the activity of the ERK1/2 and JNK signaling pathways that were all elevated in these cells. These data suggest that ADMSCs show increased rates of senescence as rats age that appear to be due to elevated Cdc42 activity. Thus, Cdc42 plays important roles in MSC senescence and differentiation potential, and pharmacological reduction of Cdc42 activity can, at least partially, rejuvenate aged MSCs.

Pre-clinical evaluation of an adult extracorporeal carbon dioxide removal system with active mixing for pediatric respiratory support.

The objective of this work was to conduct pre-clinical feasibility studies to determine if a highly efficient, active-mixing, adult extracorporeal carbon dioxide removal (ECCO2R) system can safely be translated to the pediatric population. The Hemolung Respiratory Assist System (RAS) was tested in vitro and in vivo to evaluate its performance for pediatric veno-venous applications. The Hemolung RAS operates at blood flows of 350-550 ml/min and utilizes an integrated pump-gas exchange cartridge with a membrane surface area of 0.59 m² as the only component of the extracorporeal circuit. Both acute and seven-day chronic in vivo tests were conducted in healthy juvenile sheep using a veno-venous cannulation strategy adapted to the in vivo model. The Hemolung RAS was found to have gas exchange and pumping capabilities relevant to patients weighing 3-25 kg. Seven-day animal studies in juvenile sheep demonstrated that veno-venous extracorporeal support could be used safely and effectively with no significant adverse reactions related to device operation.

Pre-clinical Evaluation of an Adult Extracoproreal Carbon Dioxide Removal System for Pediatric Application.

INTRODUCTION: Adult extracorporeal carbon dioxide removal (ECCO2R) systems and pediatric ECMO share the common objectives of having a low blood flow rate and low priming volume while safely maintaining sufficient respiratory support. The Hemolung is a highly simplified adult ECCO2R system intended for partial respiratory support in adult patients with acute hypercapnic respiratory failure. The objective of this work was to conduct pre-clinical feasibility studies to determine if a highly efficient, active-mixing, adult ECCO2R system can safely be translated to the pediatric population. METHODS: 14 healthy nonsedated juvenile sheep were used for acute (2 animals) and 7-day chronic (12 animals) in-vivo studies to evaluate treatment safety independently of respiratory related injuries. In all evaluations, we hypothesized that gas exchange capabilities of the Hemolung RAS in this model would be equivalent to the adult configuration performance at similar blood flows - minimum CO2 removal of 50 mL/min at a venous partial pressure of CO2 equal to 45 mmHg. Target blood flow rates were set to a minimum of 280 mL/min. Swan Ganz catheters were used under general anesthesia in the two acute subjects to evaluate blood gas status in the pulmonary artery. RESULTS: The Hemolung RAS was found to have adequate gas exchange and pumping capabilities for full respiratory support for subjects weighing 3 - 25 kg. The Hemolung device was estimated to provide a partial respiratory support for subjects weighing 27 - 34 kg. The seven-day studies in juvenile sheep demonstrated that veno-venous extracorporeal support could be provided safely at low flows with no significant adverse reactions related to device operation. CONCLUSION: The study outcomes suggest the potential use of the Hemolung RAS in a veno-venous pediatric configuration to safely provide respiratory support utilizing a significantly less complex system than traditional pediatric ECMO.

Heart and Lungs Protection Technique for Cardiac Surgery with Cardiopulmonary Bypass.

INTRODUCTION: Cardioplegic cardiac arrest with subsequent ischemic-reperfusion injuries can lead to the development of inflammation of the myocardium, leucocyte activation, and release of cardiac enzymes. Flow reduction to the bronchial arteries, causing low-flow lung ischemia, leads to the development of a pulmonary regional inflammatory response. Hypoventilation during cardiopulmonary bypass (CPB) is responsible for development of microatelectasis, hydrostatic pulmonary edema, poor compliance, and a higher incidence of infection. Based on these facts, prevention methods of these complications were developed. The aim of this study was to evaluate constant coronary perfusion (CCP) and the "beating heart" in combination with pulmonary artery perfusion (PAP) and "ventilated lungs" technique for heart and lung protection in cardiac surgery with CPB. METHODS: After ethical approval and written informed consent, 80 patients undergoing cardiac surgery with normothermic CPB were randomized in three groups. In the first group (22 patients), the crystalloid cardioplegia without lung ventilation/perfusion techniques were used. In the second group (30 patients), the CCP and "beating heart" without lung ventilation/perfusion techniques were used. In the third group (28 patients), the CCP with PAP and lung ventilation techniques were used. Clinical, functional parameters, myocardial damage markers (CK MB level), oxygenation index, and lung compliance were investigated. RESULTS: There were higher rates of spontaneous cardiac recovery and lower doses of inotrops in the second and third groups. Myocardial contractility function was better preserved in the second and third groups. The post-operative levels of CK-MB were lower than in control group. Three hours after surgery CK-MB levels in the second and third groups were lower by 38.1% and 33.3%, respectively. Eight hours after surgery, CK-MB levels were lower in the second and third groups by 45.9% and 47.7%, respectively. 24 hours after surgery, CK-MB levels were lower in the second and third groups by 42.0% and 42.6%, respectively, and lower by 29.7% and 27.4% 48 hours after surgery, respectively. Normalization of CK-MB levels were registered earlier in second and third groups (within 24 hours) than the control group. Oxygenation index and lung compliance were significantly higher in the third group after CPB. CONCLUSION: Our technique improved myocardial and lung function in patients, but larger prospective randomized trials are needed to definitively assess the protective effects of this technique.

Fetal Nerve Cell Transplantation in Early Post-Resuscitation Period in Rats.

INTRODUCTION: Fetal cell transplantation is a promising biomedical approach for disease treatment; however, the use of fetal cell therapy is still experimental. This research was deemed a necessity to provide evidence-based research for the application of cell transplantation as a treatment method. The aim of this study was to evaluate the effect of fetal nerve cell transplantation in rat survivors (and non-survivors) after clinical death by mechanical asphyxia. METHODS: 68 white laboratory rats were divided into two groups of identical age and sex: a control group of 12-month adult male rats (n = 26) and an experimental group (n = 42). Rats were fixed under ether anesthesia. We then blocked the oral and nasal regions with cotton wool soaked in saline solution. A four-minute clinical death though acute mechanical asphyxia was simulated by applying the method of N. Shim. After the 4-minute clinical death, we resuscitated the rats using external cardiac massage and artifical respiration. Suspension of the fetal nerve cells was injected intraperitoneally at 1mm3 per 25g at the time of cardiac activity restoration. Lactate dehydrogenase (LDH) and creatine phosphokinase (CPK) levels were examined in the homogenate cerebral cortex of reanimated animals. We recorded the survival rate during the post-resuscitation period and analyzed the integrative brain functions using anxiety-phobic status and latent inhibition. RESULTS: After fetal nerve cell transplantation, the enzymatic reactions in the experimental group became normal with a significant decrease in LDH and an increase in CPK levels compared to the control group. In the control group, 10 rats died and 16 lived (62% survival rate), while 7 rats died and 35 lived (83% survival rate) in the experimental group during the first 7 days. Rats that did not receive the treatment tended to die sooner than those in the experimental group. As a result of transplantation, the anxiety level in the experimental group was less than in the control group. Moreover, cell therapy improved the reflexes in the experimental animals. CONCLUSIONS: The study revealed the positive neuroprotective effect of the fetal nerve cells on the recovery in the early post-resuscitation period. This was confirmed by the normalization of enzymatic reactions, improvement reflective activity, and increase in the survival rate of the resuscitated animals in the group treated with fetal nerve cell transplantation. These findings warrant future research on the mechanisms associated with reflex improvement.