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We study generalizations of the forest fire model introduced in [4] and [10] by allowing the rates at which the trees grow to depend on their location, introducing long-range burning, as well as a continuous-space generalization of the model. We establish that in all the models in consideration the expected time required to reach a site at distance x from the origin is of order $(\!\log x)^{(\!\log 2)^{-1}+\delta}$ for any $\delta>0$ .

Metabolic abnormalities such as obesity, insulin resistance, and type 2 diabetes mellitus are known to be associated with adipose tissue inflammation and impaired secretion of cytokines. Anti-inflammatory cytokine interleukin-4 (IL-4) was found to promote insulin sensitivity, glucose tolerance, and reduce lipid accumulation

Calvarial bone healing is challenging, especially for individuals with osteoporosis because stem cells from osteoporotic patients are highly prone to adipogenic differentiation. Based on previous findings that chondrogenic induction of adipose-derived stem cells (ASCs) can augment calvarial bone healing, we hypothesized that activating chondroinductive Sox Trio genes (Sox5, Sox6, Sox9) and repressing adipoinductive genes (C/ebp-α, Ppar-γ) in osteoporotic ASCs can reprogram cell differentiation and improve calvarial bone healing after implantation. However, simultaneous gene activation and repression in ASCs is difficult. To tackle this problem, we built a CRISPR-BiD system for bi-directional gene regulation. Specifically, we built a CRISPR-AceTran system that exploited both histone acetylation and transcription activation for synergistic Sox Trio activation. We also developed a CRISPR interference (CRISPRi) system that exploited DNA methylation for repression of adipoinductive genes. We combined CRISPR-AceTran and CRISPRi to form the CRISPR-BiD system, which harnessed three mechanisms (transcription activation, histone acetylation, and DNA methylation). After delivery into osteoporotic rat ASCs, CRISPR-BiD significantly enhanced chondrogenesis and in vitro cartilage formation. Implantation of the engineered osteoporotic ASCs into critical-sized calvarial bone defects significantly improved bone healing in osteoporotic rats. These results implicated the potential of the CRISPR-BiD system for bi-directional regulation of cell fate and regenerative medicine.

Non-shivering thermogenesis takes place in brown and beige adipocytes and facilitates cold tolerance and acclimation. However, thermogenesis in adipose tissue also was found to be activated in metabolic overload states for fast utilization of nutrients excess. This observation spurred research interest in mechanisms of thermogenesis regulation for metabolic overload and obesity prevention. One of proposed regulators of thermogenic efficiency in adipocytes is the dynamics of mitochondria, where thermogenesis takes place. Indeed, brown and beige adipocytes exhibit fragmented round-shaped mitochondria, while white adipocytes have elongated organelles with high ATP synthesis. Mitochondrial morphology can determine uncoupling protein 1 (UCP1) content, efficiency of catabolic pathways and electron transport chain, supplying thermogenesis. This review will highlight the co-regulation of mitochondrial dynamics and thermogenesis and formulate hypothetical ways for excessive nutrients burning in response to mitochondrial morphology manipulation.

Balls-in-bins models describe a random sequential allocation of infinitely many balls into a finite number of bins. In these models a ball is placed into a bin with probability proportional to a given function (feedback function), which depends on the number of existing balls in the bin. Typically, the feedback function is the same for all bins (symmetric feedback), and there are no constraints on the number of balls in the bins. In this paper we study versions of BB models with two bins, in which the above assumptions are violated. In the first model of interest the feedback functions can depend on a bin (BB model with asymmetric feedback). In the case when both feedback functions are power law and superlinear, a single bin receives all but finitely many balls almost surely, and we study the probability that this happens for a given bin. In particular, under certain initial conditions we derive the normal approximation for this probability, which generalizes the result in [5] obtained in the case of the symmetric feedback. The main part of the paper concerns the BB model with asymmetric feedback evolving subject to certain constraints on the numbers of allocated balls. The model can be interpreted as a transient reflecting random walk in a curvilinear wedge, and we obtain a complete classification of its long term behavior.

Mesenchymal stem/stromal cells (MSCs) represent a promising tool to treat cardiovascular diseases. One mode of action through which MSCs exert their protective effects is secretion of extracellular vesicles (EVs). Recently we demonstrated that rat adipose-derived MSC overexpressing stem cell factor (SCF) can induce endogenous regenerative processes and improve cardiac function. In present work we isolated EVs from intact or SCF-overexpressing rat MSC and analyzed microarray datasets of their miRNA cargo. We uncovered a total of 95 differentially expressed miRNAs and identified 2 miRNAs significantly up-regulated in SCF-MSCs. One of them - rno-miR-344a-2, associated with aging and regulation of a-SMA was also increased in EVs from GFP-MSC that may indicate intrinsic changes in MSC after viral transduction. About 80 miRNA were downregulated in EVs from SCF- or GFP-MSC. We assembled the miRNA-based network and found several nodes of target genes among which Vim Sept3 and Vsnl1 are involved in regulation of cellular migration that consistent with our previous EVs data. Topological analyses of network also revealed among downregulated miRNAs- rno-miRNA-128-3p that regulates plenty of targets presumably associated with chemokine signaling pathways. Overall, our data suggest that genetic modification of MSC have a great impact on their miRNA composition and provide novel insights into the regulatory networks underlying EVs effects.

Ex vivo, gene therapy is a powerful approach holding great promises for the treatment of both genetic and acquired diseases. Adeno-associated virus (AAV) vectors are a safe and efficient delivery system for modification of mesenchymal stem cells (MSC) that could maximize their therapeutic benefits. Assessment of MSC viability and functional activity after infection with new AAV serotypes is necessary, due to AAV tropism to specific cell types. We infected human and rat adipose-tissue MSC with hybrid AAV-DJ serotype vectors carrying GFP and SCF genes. GFP expression from AAV-DJ was about 1.5-fold superior to that observed with AAV-2 and lasted for at least 21 days as was evaluated by flow cytometry and fluorescence microscopy. AAV-DJ proves to be suitable for the infection of rat and human MSC with a similar efficiency. Infected MSC were still viable but showed a 25-30% growth-rate slowdown. Moreover, we found an increase of SERPINB2 mRNA expression in human MSC while expression of other oxidative stress markers and extracellular matrix proteins was not affected. These results suggest that there is a differential cellular response in MSC infected with AAV viral vectors, which should be taken into account as it can affect the expected outcome for the therapeutic application., Summary: Adeno-associated viral vectors are widely used for gene delivery but their impact on the different cell types varies greatly and is not well understood. We describe effects of two most popular AAV serotypes on mesenchymal stromal cells of rat and human origin.

Objective: We have performed the comparative study of basal state of SGK-dependent signaling among obese patients with/without type 2 diabetes mellitus (T2DM). We have accomplished correlation analysis of glucose metabolism and incretin profile parameters against phosphorylation and expression parameters for SGK1 and its substrate NDRG1. Methods: 36 patients with long (>10 years) and morbid (BMI>35 kg/m2) obesity, 18 of which had normal glucose tolerance (NGT) and 18 had T2DM were enrolled in this study. Hyperinsulinemic-euglycemic clamp test and HOMA-IR were used to evaluate the insulin resistance. Blood samples taken at 0, 30 and 120 min of food load test were used to assess incretin profile, insulin and glucose levels. Biopsies from subcutaneous and omental fat depots were obtained during bariatric surgery for all patients and signaling states were analyzed by western blot. Results: Analysis of SGK signaling for subcutaneous fat has shown single significant intergroup difference: enhancing of pSGK-S422 phosphorylation in T2DM group, but also pNDRG-T346 level has tendency to accumulation in subcutaneous fat of NGT patients. Analysis of SGK signaling for omental fat has shown similar results: in this case accumulation of pNDRG-T346 in NGT patients was statistically significant. Correlation analysis has shown strong direct correlation of pNDRG-T346 level with BMI and AUC for GLP-1 and reverse correlation of pNDRG-T346 with Hb1Ac and AUC for glucagon. For pSGK-S422 we have observed opposite characters of correlations with the similar parameters of carbohydrate metabolism and incretin profile. Conclusions: In present work we have taken more patients and have shown critical relevance and general character of stress-dependent SGK1-NDRG1 signal axis as a marker of insulin resistance for different fat depots. Disclosure I. Stafeev: None. A. V. Vorotnikov: None. Y. V. Parfyonova: None. M. V. Shestakova: None. I. Sklyanik: None. E. Mamontova: None. S. Michurina: None. E. Shestakova: None. K. Yahyaev: None. A. Yurasov: None. E. Ratner: None. M. Menshikov: None. Funding Russian Science Foundation (17-15-01435)

Obesity is accompanied by dyslipidemia, hypoxia, endoplasmic reticulum (ER) stress, and inflammation, representing the major risk factor for the development of insulin resistance (IR) and type 2 diabetes. We modeled these conditions in cultured 3T3-L1 adipocytes and studied their effect on insulin signaling, glucose uptake, and inflammatory response via activation of stress-dependent JNK1/2 kinases. Decreased insulin-induced phosphorylation of the insulin cascade components IRS, Akt, and AS160 was observed under all tested conditions (lipid overloading of cells by palmitate, acute inflammation induced by bacterial lipopolysaccharide, hypoxia induced by Co2+, and ER stress induced by brefeldin A). In all the cases, except the acute inflammation, glucose uptake by adipocytes was reduced, and the kinetics of JNK1/2 activation was bi-phasic exhibiting sustained activation for 24 h. By contrast, in acute inflammation, JNK1/2 phosphorylation increased transiently and returned to the basal level within 2-3 h of stimulation. These results suggest a critical role of sustained (latent) vs. transient (acute) inflammation in the induction of IR and impairment of glucose utilization by adipose tissue. The components of the inflammatory signaling can be promising targets in the development of new therapeutic approaches for preventing IR and type 2 diabetes.

Background Obesity and type 2 diabetes mellitus (T2DM) are among the most important morbidity factors. In this study we tested the hypothesis that low proliferative potential of adipose derived stromal cells (ADSC) associates with reduced formation of new fat depots, excess accumulation of fat in the functional adipocytes and their hypertrophy, resulting in fat inflammation and insulin resistance. Methods We screened two groups of obese patients with or without T2DM, matched for BMI, age, and duration of obesity to test the hypothesis that hypertrophy and decreased renewal of adipocytes may underlie transition from obesity to T2DM. All patients were matched for carbohydrate metabolism (fasting blood glucose level, glycated hemoglobin, HOMA-IR index and M-index). The subcutaneous and omental fat tissue biopsies were obtained during bariatric surgery from obese individuals with or without T2DM. The morphology and immunophenotype of subcutaneous and omental fat was assessed in frozen tissue sections. ADSC were isolated from both types of fat tissue biopsies and screened for morphology, proliferative potential and inflammatory status. Results The non-diabetic patients had normal carbohydrate metabolism and moderate insulin resistance measured by HOMA-IR and hyperinsulinemic clamp (M-index), while T2DM patients were extremely insulin resistant by both indexes. The average size of diabetic adipocytes was higher than that of non-diabetic in both subcutaneous and omental fat tissues, indicating adipocyte hypertrophy in T2DM. Both these tissues contained higher level of macrophage infiltration and increased M1-like to M2-like ratio of macrophage subpopulations, suggesting increased fat inflammation in T2DM. This was confirmed by increased activatory phosphorylation of stress-induced JNK1/2 in diabetic ADSC. Conclusion These results suggest that blunted proliferation and increased hypertrophy of diabetic ADSC may lead to reduced insulin sensitivity via increased inflammation mediated by M1 macrophages and JNK1/2 pathway.

Incretin hormones analogues, including glucagon-like peptide type 1 (GLP-1), exhibit complex glucose-lowering, anorexigenic, and cardioprotective properties. Mechanisms of action of GLP-1 and its analogues are well known for pancreatic β-cells, hepatocytes, and other tissues. Nevertheless, local effects of GLP-1 and its analogues in adipose tissue remain unclear. In the present work effects of the GLP-1 synthetic analogue, liraglutide, on adipogenesis and insulin sensitivity of the 3T3-L1 adipocytes were examined. Enhancement of insulin sensitivity of mature adipocytes by the GLP-1 synthetic analogue liraglutide mediated by adenylate cyclase was demonstrated. The obtained results imply existence of the positive direct insulin-sensitizing effect of liraglutide on mature adipocytes.

In the modern world obesity and insulin resistance contribute to a high impact on the structure of mortality. Basic research and pharmacological screenings for the search of new targets and insulin sensitizers require relevant cell models of adipocytes. Today the 3T3-L1 preadipocytes cell line is a widely used mouse-based model for investigation of adipocyte biology. Nonetheless, animal studies cannot be transferred directly in human research and nowadays the search for relevant and renewable cell models of human adipocyte is of undeniable importance. In the present study, we have compared pooled culture of human adipose-derived stem cells (ADSC) with immortalized ADSC cell line ASC52Telo. Both cell types had mesenchymal stem cell phenotype verified by flow cytometry. However, the efficacy of adipogenic differentiation, stimulation of FABP4 and PPARg protein expressions, and glucose uptake stimulation by insulin were reduced for ASC52Telo-derived adipocytes in comparison with ADSC-derived adipocytes. In addition, the analysis of insulin signaling has shown impaired phosphorylation of IRS1 and AS160 in ASC52Telo-derived cells. In summary, we have shown that immortalized cell line of human ADSC ASC52Telo have mesenchymal stem cell phenotype. Nevertheless, ASC52Telo-derived adipocytes demonstrate impaired adipogenesis and insulin sensitivity that are the main properties of healthy adipocytes.

Cell therapy of the post-infarcted myocardium is still far from clinical use. Poor survival of transplanted cells, insufficient regeneration, and replacement of the damaged tissue limit the potential of currently available cell-based techniques. In this study, we generated a multilayered construct from adipose-derived mesenchymal stromal cells (MSCs) modified to secrete stem cell factor, SCF. In a rat model of myocardium infarction, we show that transplantation of SCF producing cell sheet induced activation of the epicardium and promoted the accumulation of c-kit positive cells in ischemic muscle. Morphometry showed the reduction of infarct size (16%) and a left ventricle expansion index (0.12) in the treatment group compared to controls (24&ndash, 28%, 0.17&ndash, 0.32). The ratio of viable myocardium was more than 1.5-fold higher, reaching 49% compared to the control (28%) or unmodified cell sheet group (30%). Finally, by day 30 after myocardium infarction, SCF-producing cell sheet transplantation increased left ventricle ejection fraction from 37% in the control sham-operated group to 53%. Our results suggest that, combining the genetic modification of MSCs and their assembly into a multilayered construct, we can provide prolonged pleiotropic effects to the damaged heart, induce endogenous regenerative processes, and improve cardiac function.

Background Obesity is the main risk factor of latent inflammation, which leads to insulin resistance (IR) which can transform to type 2 diabetes mellitus (T2DM). Today several groups of drugs are used to correct T2DM and its complications. The most perspective treatment is the use of glucagon-like peptide-1 (GLP-1) receptor agonists, such as liraglutide, that affect the insulin exocytosis in pancreatic β-cells. The metabolic pathways in these cells are well studied, but liraglutide's effects on other insulin-sensitive tissues, such as adipose tissue, remain unclear. Purpose We wanted to investigate the effect of the synthetic analogue of GLP-1 liraglutide on insulin sensitivity and on inflammatory and mitogenic signaling pathways in 3T3-L1 adipocytes. Methods We studied the effects of liraglutide on the kinetics of inflammatory and mitogenic pathways and insulin sensitivity in 3T3-L1 adipocytes, which were differentiated according to standard protocol with insulin, IBMX and dexamethasone. IR was induced by treatment with 1mM free fatty acids for 24 hours. Activities of insulin, mitogenic and inflammatory signaling pathways were analyzed by Western blotting with phospho-specific antibodies. Insulin sensitivity was also assessed by insulin-stimulated [3H]-deoxyglucose uptake analysis. Results We have showed that liraglutide promotes the decrease in expression of kinases JNK and ERK. So, under these results, we had a hypothesis that liraglutide changes cAMP-dependent regulation of transcription. In order to check it we have used the inhibitor of adenylyl cyclase (SQ22536) to see whether there will be any effects of liraglutide. As we suspected there was no effect, so our hypothesis of the liraglutide-stimulated activation of cAMP-dependent pathway was confirmed. In the model of IR adipocytes liraglutide promotes the increase of total amount of IRS and Akt and increased phosphorylation of pAkt-T308. When SQ22536 was added there was no effect of liraglutide on insulin sensitivity. Conclusion These results suggest the action of liraglutide in 3T3-L1 adipocytes via transcriptional regulation and insulin sensitivity control. According to our hypothesis, GLP-1 analogue liraglutide can influence systemic insulin sensitivity via regulation of adipose tissue metabolism. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): Russian Science Foundation

Objective: In our study we have compared basal insulin and mTOR signaling in subcutaneous fat of obese T2DM vs. obese subjects with normal glucose tolerance (NGT). We have performed correlation analysis of phosphorylation’s parameters against clinical parameters of carbohydrate metabolism and incretin secretion profiles. Methods: 22 patients with long (>10 years) and morbid (BMI > 35 kg/m2) obesity, 12 of which had NGT and 10 had T2DM were enrolled in this study. Hyperinsulinemic-euglycemic clamp test and HOMA-IR were used to measure insulin resistance. Blood samples taken at 0, 30 and 120 min of food load test were used to assess incretin profile, insulin and glucose levels. Amount of total and visceral fat was determined by bioelectrical impedance analysis. Subcutaneous fat biopsies were obtained during bariatric surgery for all patients and signaling state was analyzed by western blots. Results: As assessed by western blots of insulin receptor substrate (IRS), Akt, Raptor, Rictor, mTOR and S6K1, the basal insulin signaling and mTORC activities were comparable in NGT and T2DM groups, whereas phosphorylation of AS160 (pAS160-S318) was significantly lower and serum and glucocorticoid-induced kinase (SGK; pSGK-S422) was significantly higher in T2DM group. Various correlations were found between the degree of insulin resistance and amount of visceral fat, changes in incretin profile, glucose metabolic parameters and phosphorylation level of AS160, incretin secretion profile and phosphorylated levels of AS160 or SGK1. Conclusions: Altered phosphorylation of AS160 and SGK1 is associated with obese T2DM phenotype and impaired incretin profile. We think that AS160 and SGK1 phosphorylations can be important markers of the prediabetes-to-diabetes transition. Disclosure I. Stafeev: None. I. Sklyanik: None. S. Michurina: None. E. Shestakova: Employee; Spouse/Partner; AstraZeneca. Speaker’s Bureau; Self; Abbott, AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Novartis Pharma K.K., Novo Nordisk A/S, Sanofi-Aventis, Takeda Pharmaceutical Company Limited. A. Yurasov: None. K. Yahyaev: None. A. Karmadonov: None. E. Ratner: None. M. Menshikov: None. A.V. Vorotnikov: None. Y.V. Parfyonova: None. M.V. Shestakova: None. Funding Russian Science Foundation (17-15-01435)

There are several models of T2DM remission after bariatric surgery (ABCD, DiaRem, DRS), but none of them includes insulin resistance. Moreover these models are not suitable for early prediction of T2DM remission (within several months after surgery). Methods: We included 42 patients with T2DM and morbid obesity (BMI 42.3 [38.9; 48.1] kg/m2) after bariatric surgery (16 pts after restrictive procedures and 26 pts after bypass surgery). Insulin resistance was measured by hyperinsulienic euglycaemic test with M-index estimation (mg/kg/min) and HOMA-IR before the surgery. Glycaemia normalization was assessed by self-monitoring of blood glucose (FPG < 110 mg/dl (6.1 mmol/l) and postprandial PG < 140 mg/dl (7.8 mmol/l) in 1 month after surgery) as well as HbA1c < 6.0% (42 mmol/mol) in 3 months after surgery. ROC-curve identified insulin resistance predictive value of blood glucose normalization after bariatric surgery. Statistical analysis was performed using SPSS v.23.0. Results: All patients had severe insulin resistance at baseline (median M-index before surgery 1.535 mg/kg/min, HOMA-IR 10.0). Within 1 month after surgery 7 patients (16,7%) reached blood glucose normalization, within 3 months - 22 patients (52,4%), within 6 months - 31 patient (73,8%), in 12 months - 35 patients (83,3%). ROC-analysis showed that M-index within 1st month after surgery was predictive of blood glucose normalization; insulin resistance cut-off value was 1.876 mg/kg/min (Youden’s index). HOMA-IR and M-index in 3, 6 and 12 months after surgery didn’t predict glycaemia normalization. Conclusion: Baseline insulin resistance value defined as M-index > 1.876 mg/kg/min can be used to predict early blood glucose normalization within 1 month after bariatric surgery. Disclosure I. Sklyanik: None. E. Shestakova: Employee; Spouse/Partner; AstraZeneca. Speaker’s Bureau; Self; Abbott, AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Novartis Pharma K.K., Novo Nordisk A/S, Sanofi-Aventis, Takeda Pharmaceutical Company Limited. I. Stafeev: None. S. Michurina: None. A. Karmadonov: None. A.V. Vorotnikov: None. K. Yahyaev: None. A. Yurasov: None. M. Menshikov: None. A. Mayorov: Speaker’s Bureau; Self; Abbott, LifeScan, Inc., Novo Nordisk A/S, Roche Diabetes Care, Sanofi-Aventis. Y.V. Parfyonova: None. M.V. Shestakova: None. Funding Russian Science Foundation (17-15-01435)

Background: Under normal physiological conditions, adipose derived stem cells (ADSC) maintain adipose tissue homeostasis by responding to metabolic loading through proliferation and differentiation. Nevertheless, in T2DM their properties might be compromised. ADSC give rise to thermogenic beige adipocytes that make a significant contribution into excess energy utilization in obesity. We compared ADSC response to beiging inductors in obese patients with type 2 diabetes mellitus (T2DM) and with normal glucose tolerance (NGT). Methods: We collected subcutaneous fat biopsies from 5 obese NGT (BMI>35kg/m2) and 5 obese T2DM patients during bariatric surgery. ADSC were enzymatically isolated and underwent white and beige adipogenic differentiation. UCP-1 level was evaluated by RT-PCR and Western blot. Expression of lipid metabolism and electron transport chain (ETC) genes were analyzed by RT-PCR. ROS production was evaluated by fluorescent microscopy. Results: UCP-1 expression was decreased in beige adipocytes from T2DM patients in mRNA and protein levels. Nevertheless, expression and phosphorylation of lipolytic proteins were equal in beige adipocytes of NGT and T2DM groups. Expression analysis of ETC genes also has not shown any statistically significant differences. All the while, we revealed increased mitochondrial ROS production in T2DM beige adipocytes during beige differentiation. Conclusions: These results indicate association of ADSC thermogenic potential and T2DM development. Decreased UCP1 level in complex with normal lipolysis and ETC activity in beige adipocytes from T2DM patients may be liable to elevated ROS level, known to initiate mitochondria damage and insulin resistance. Disclosure S. Michurina: None. I. Stafeev: None. I. Sklyanik: None. E. Shestakova: Employee; Spouse/Partner; AstraZeneca. Speaker’s Bureau; Self; Abbott, AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Novartis Pharma K.K., Novo Nordisk A/S, Sanofi-Aventis, Takeda Pharmaceutical Company Limited. A. Yurasov: None. K. Yahyaev: None. E. Ratner: None. M. Menshikov: None. M.V. Shestakova: None. Y.V. Parfyonova: None. Funding Russian Science Foundation (17-15-01435)

Fix integers $d \geq 2$ and $k\geq d-1$. Consider a random walk $X_0, X_1, \ldots$ in $\mathbb{R}^d$ in which, given $X_0, X_1, \ldots, X_n$ ($n \geq k$), the next step $X_{n+1}$ is uniformly distributed on the unit ball centred at $X_n$, but conditioned that the line segment from $X_n$ to $X_{n+1}$ intersects the convex hull of $\{0, X_{n-k}, \ldots, X_n\}$ only at $X_n$. For $k = \infty$ this is a version of the model introduced by Angel et al., which is conjectured to be ballistic, i.e., to have a limiting speed and a limiting direction. We establish ballisticity for the finite-$k$ model, and comment on some open problems. In the case where $d=2$ and $k=1$, we obtain the limiting speed explicitly: it is $8/(9\pi^2)$., Comment: 31 pages, 3 figures; v2: minor revisions

Resident cardiac progenitor cells reside in the adult heart and govern myocardial homeostasis and repair after injury. Many experimental and clinical studies are being completed with encouraging results. However, the mechanisms of the therapeutic action of CPC remain poorly understood. Initially they were explained by the ability of CPC to differentiate into cardiomyocytes and vascular cells, recently their regenerative effects are mainly explained by secretion biologically active molecules and the release of exosomes, which promote activation of the regenerative program in the heart cells. The aim of the present study is to assess the effect of intramyocardial CPC transplantation on the activation of the vasculogenic pool of epicardial cells. In our study we ligated the anterior descending coronary artery in the hearts of male Wistar rats and intramyocardial injections of a fluorescently labeled (CM-DIL+) CPC or control medium were performed. Fourteen days after transplantation, CPC retained viability, proliferation properties and some cells showed signs of vasculogenic differentiation. We did not find significant differences in the infarct size between two groups assessed by morphometric studies. However, CPC transplantation attenuated adverse remodeling: we found reduction in left ventricular dilatation, severity of transmural injury and activation of arteriogenesis in the border zone. By immunofluorescence staining of myocardial sections, obtained after CPC transplantation, we found a significant increase the number of Wt1+ cells in the epicardium, indicating activation of the epithelial-mesenchymal transition and the formation of epicardial progenitor cells (EPC). EPC migrated to the myocardium, some of them coexpressed markers CD31 (Pecam), alpha-smooth muscle actin (a-SMA), and participated in the new vessels formation. Thus, intramyocardial CPC transplantation increased the vascularization of the myocardium by differentiation of the transplanted cells, as well as the activation of vasculogenic epicardial cells, which can contribute the reduction of negative cardiac remodeling.

A new trend in modern experimental cardiology is the development of approaches to correction of reparation after myocardial infarction (MI) with the use of specific effects on immune cells. One of the main targets for such interventions is the process of macrophage's polarization in the infarction zone. Proinflammatory M1‑macrophages contribute to hampered myocardial repair, in contrast to M2‑macrophages that promote regeneration. Currently, there are two main ways of targeted delivery of agents necessary for macrophage reprogramming - inlipoid and inglycan-encapsulated particles. As modulating agents, small interfering RNA and other genetic constructions are usually used. Both these approaches are currently awaiting their translation into cardiology. The most physiological approach to reprogramming of immune cells may consist in attempts to switch the metabolism of the immune cell from glycolytic to oxidative, which allows macrophages to switch from M1 to M2 phenotype. Among possible targets for macrophage reprogramming, it is worthwhile to isolate the protein complex mTORC1, the blocking of which promotes oxidative metabolism, and the transcription factor HIF-1α, the blocking of which also facilitates the switching of the metabolism from glycolytic to oxidative one.

Background Obesity, remaining a topical issue of modern medicine, leads to development of latent inflammation and insulin resistance in adipose tissue with subsequent development of type 2 diabetes mellitus (T2DM). Among patients with obesity, patients with obesity and normal glucose tolerance (NGT) are often encountered. In our study we have tested the hypothesis that low proliferative potential of adipose derived stromal cells (ADSC) associates with reduced formation of new fat depots, excess accumulation of fat in the functional adipocytes and their hypertrophy, resulting in fat inflammation and insulin resistance. Methods We screened two groups of obese patients with or without T2DM, matched for BMI, age, and duration of obesity to test the hypothesis that hypertrophy and decreased renewal of adipocytes may underlie transition from obesity to T2DM. All patients were matched for carbohydrate metabolism (fasting blood glucose level, glycated hemoglobin, HOMA-IR index and M-index). The subcutaneous and omental fat tissue biopsies were obtained during bariatric surgery from obese individuals with or without T2DM. The morphology and immunophenotype of subcutaneous and omental fat was assessed in frozen tissue sections. ADSC were isolated from both types of fat tissue biopsies and screened for morphology, proliferative potential and inflammatory status. Results The non-diabetic patients had normal carbohydratemetabolism andmoderate insulin resistancemeasured byHOMA-IR and hyperinsulinemic clamp (M-index),while T2DM patientswere extremely insulin resistant by both indexes. The average size of diabetic adipocytes was higher than that of non-diabetic in both subcutaneous and omental fat tissues, indicating adipocyte hypertrophy in T2DM. We have shown that ADSC from T2DM patients had significantly higher level of inflammation. According to measurement of p62 expression and LC3 modification we can say that ADSC from T2DM patients have less autophagy level compare with ADSC from NGT patients. Immunohistochemistry have shown that patients with T2DM have much more infiltration of CD68+-cells in subcutaneous and omental adipose tissue and immunophenotype (balance of M1-M2 macrophages) of adipose tissue at this patients shift toward inflammatory state. Conclusion These results suggest that decreased proliferation and increased hypertrophy of diabetic ADSC may lead to reduced insulin sensitivity via increased inflammation mediated by M1-macrophages and JNK1/2 pathway. Acknowledgement/Funding This work was supported by RSF grant #17-15-01435

Objective To compare basal insulin and mTOR signaling in subcutaneous fat of obese T2DM vs. obese subjects with normal glucose tolerance (NGT), and correlate it with clinical parameters of carbohydrate metabolism and incretin secretion profiles. Methods Recruited were 22 patients with long (>10 years) and morbid (BMI > 35 kg/m2) obesity, 12 of which had NGT and 10 had T2DM. Hyperinsulinemic-euglycemic clamp test and HOMA-IR were used to measure insulin resistance. Blood samples taken at 0, 30 and 120 min of food load test were used to assess incretin profile, insulin and glucose levels. Amount of total and visceral fat was determined by bioelectrical impedance analysis. Subcutaneous fat biopsies were obtained during bariatric surgery for all patients and analyzed by western blots. Results As assessed by western blots of insulin receptor substrate (IRS), Akt, Raptor, Rictor, mTOR and S6K1, the basal insulin signaling and mTORC activities were comparable in NGT and T2DM groups, whereas phosphorylation of AS160 was significantly lower and that of serum and glucocorticoid-induced kinase (SGK) was significantly higher in T2DM group. Various correlations were found between the degree of insulin resistance and amount of visceral fat, changes in incretin profile, glucose metabolic parameters and phosphorylation level of AS160, incretin secretion profile and phosphorylated levels of AS160 or SGK1. Conclusion Altered phosphorylation of AS160 and SGK1 is associated with obese T2DM phenotype.

We study the recurrence/transience phase transition for Markov chains on ${\mathbb{R} }_{+}$, $\mathbb{R} $, and ${\mathbb{R} }^{2}$ whose increments have heavy tails with exponent in $(1,2)$ and asymptotically zero mean. This is the infinite-variance analogue of the classical Lamperti problem. On ${\mathbb{R} }_{+}$, for example, we show that if the tail of the positive increments is about $c y^{-\alpha }$ for an exponent $\alpha \in (1,2)$ and if the drift at $x$ is about $b x^{-\gamma }$, then the critical regime has $\gamma = \alpha -1$ and recurrence/transience is determined by the sign of $b + c\pi \operatorname{cosec} (\pi \alpha )$. On $\mathbb{R} $ we classify whether transience is directional or oscillatory, and extend an example of Rogozin & Foss to a class of transient martingales which oscillate between $\pm \infty $. In addition to our recurrence/transience results, we also give sharp results on the existence/non-existence of moments of passage times.

Objective Adipose derived stem cells (ADSC) are defective in metabolic disorders in various functionalities and properties including differentiation, multipotent state, metabolism and immunomodulation. However, the role of ADSC beiging potential in promoting of type 2 diabetes mellitus (T2DM) development remains unclear. Here we uncover association between potential of subcutaneous ADSC to beige differentiation and T2DM in patients with obesity. Methods ADSC were isolated from subcutaneous adipose tissue of patients with long morbid obesity (BMI > 35 kg/m2) and normal glucose tolerance (NGT) or T2DM. ADSC were differentiated into white or beige adipocytes and levels of thermogenic markers, lipid metabolism and electron transport chain (ETC) genes was analyzed by Western blotting and RT-PCR. ROS production was estimated by fluorescent microscopy. Results We have shown decreased UCP-1 expression in beige adipocytes from T2DM patients. Nevertheless, signal and expression activities of lipolysis were equal in NGT and T2DM beige adipocytes. Expression analysis of ETC genes also has not shown any statistically significant differences. Interestingly, we revealed increased mitochondrial ROS production in T2DM beige adipocytes during beige differentiation. Conclusions In summary, compromised UCP1 expression in beige adipocytes of T2DM patients may cause increase of mitochondrial ROS. Elevated oxidative level is liable to act as damaging mechanism leading to insulin resistance or, alternatively, serve as compensatory mechanism for thermogenesis activation.

This paper concerns the long term behaviour of a growth model describing a random sequential allocation of particles on a finite graph. The probability of allocating a particle at a vertex is proportional to a log-linear function of numbers of existing particles in a neighbourhood of a vertex. When this function depends only on the number of particles in the vertex, the model becomes a special case of the generalised Polya urn model. In this special case all but finitely many particles are allocated at a single random vertex almost surely. In our model interaction leads to the fact that, with probability one, all but finitely many particles are allocated at vertices of a maximal clique.

We study a random walk on a complex of finitely many half-lines joined at a common origin; jumps are heavy-tailed and of two types, either one-sided (towards the origin) or two-sided (symmetric). Transmission between half-lines via the origin is governed by an irreducible Markov transition matrix, with associated stationary distribution $\mu_k$. If $\chi_k$ is $1$ for one-sided half-lines $k$ and $1/2$ for two-sided half-lines, and $\alpha_k$ is the tail exponent of the jumps on half-line $k$, we show that the recurrence classification for the case where all $\alpha_k \chi_k \in (0,1)$ is determined by the sign of $\sum_k \mu_k \cot ( \chi_k \pi \alpha_k )$. In the case of two half-lines, the model fits naturally on $\mathbb{R}$ and is a version of the oscillating random walk of Kemperman. In that case, the cotangent criterion for recurrence becomes linear in $\alpha_1$ and $\alpha_2$; our general setting exhibits the essential non-linearity in the cotangent criterion. For the general model, we also show existence and non-existence of polynomial moments of return times. Our moments results are sharp (and new) for several cases of the oscillating random walk; they are apparently even new for the case of a homogeneous random walk on $\mathbb{R}$ with symmetric increments of tail exponent $\alpha \in (1,2)$., Comment: 35 pages, 2 figures

This paper concerns the long term behaviour of a growth model describing a random sequential allocation of particles on a finite cycle graph. The model can be regarded as a reinforced urn model with graph-based interactions. It is motivated by cooperative sequential adsorption, where adsorption rates at a site depend on the configuration of existing particles in the neighbourhood of that site. Our main result is that, with probability one, the growth process will eventually localise either at a single site, or at a pair of neighbouring sites., 31 pages, 2 figures

The adult heart contains small populations of multipotent cardiac progenitor cells (CPC) that present a convenient and efficient resource for treatment of myocardial infarction. Several clinical studies of direct CPC delivery by injection have already been performed but showed low engraftment rate that limited beneficial effects of procedure. «Cell sheet» technology has been developed to facilitate longer retention of grafted cells and show new directions for cell-based therapy using this strategy. In this study we hypothesized that СPC-based cell sheet transplantation could improve regeneration after myocardial infarction. We demonstrated that c-kit+ CPC were able to form cell sheets on temperature-responsive surfaces. Cell sheet represented a well-organized structure, in which CPC survived, retained ability to proliferate, expressed progenitor cell marker Gata-4 formed connexin-43+ gap junctions, and were surrounded by significant amount of extracellular matrix proteins. Transplantation of cell sheets after myocardial infarction resulted in CPC engraftment as well as their proliferation, migration, and differentiation; cell sheets also stimulated neovascularization and cardiomyocyte proliferation in underlining myocardium and ameliorated left ventricular remodeling. Obtained data strongly supported potential use of CPC sheet transplantation for repair of damaged heart.

Tissue regeneration requires coordinated "teamwork" of growth factors, proteases, progenitor and immune cells producing inflammatory cytokines. Mesenchymal stem cells (MSC) might play a pivotal role by substituting cells or by secretion of growth factors or cytokines, and attraction of progenitor and inflammatory cells, which participate in initial stages of tissue repair. Due to obvious impact of inflammation on regeneration it seems promising to explore whether inflammatory factors could influence proangiogenic abilities of MSC. In this study we investigated effects of TNF-α on activity of adipose-derived stem cells (ADSC). We found that treatment with TNF-α enhances ADSC proliferation, F-actin microfilament assembly, increases cell motility and migration through extracellular matrix. Exposure of ADSC to TNF-α led to increased mRNA expression of proangiogenic factors (FGF-2, VEGF, IL-8, and MCP-1), inflammatory cytokines (IL-1β, IL-6), proteases (MMPs, uPA) and adhesion molecule ICAM-1. At the protein level, VEGF, IL-8, MCP-1, and ICAM-1 production was also up-regulated. Pre-incubation of ADSC with TNF-α-enhanced adhesion of monocytes to ADSC but suppressed adherence of ADSC to endothelial cells (HUVEC). Stimulation with TNF-α triggers ROS generation and activates a number of key intracellular signaling mediators known to positively regulate angiogenesis (Akt, small GTPase Rac1, ERK1/2, and p38 MAP-kinases). Pre-treatment with TNF-α-enhanced ADSC ability to promote growth of microvessels in a fibrin gel assay and accelerate blood flow recovery, which was accompanied by increased arteriole density and reduction of necrosis in mouse hind limb ischemia model. These findings indicate that TNF-α plays a role in activation of ADSC angiogenic and regenerative potential.