Extracellular matrix hyaluronan modulates fat cell differentiation and primary cilia dynamics.

Hyaluronan is an important extracellular matrix component, with poorly documented physiological role in the context of lipid-rich adipose tissue. We have investigated the global impact of hyaluronan removal from adipose tissue environment by in vitro exposure to exogenous hyaluronidase (or heat inactivated enzyme). Gene set expression analysis from RNA sequencing revealed downregulated adipogenesis as a main response to hyaluronan removal from human adipose tissue samples, which was confirmed by hyaluronidase-mediated inhibition of adipocyte differentiation in the 3T3L1 adipose cell line. Hyaluronidase exposure starting from the time of induction with the differentiation cocktail reduced lipid accumulation in mature adipocytes, limited the expression of terminal differentiation marker genes, and impaired the early induction of co-regulated Cebpa and Pparg mRNA. Reduction of Cebpa and Pparg expression by exogenous hyaluronidase was also observed in cultured primary preadipocytes from subcutaneous, visceral or brown adipose tissue of mice. Mechanistically, inhibition of adipogenesis by hyaluronan removal was not caused by changes in osmotic pressure or cell inflammatory status, could not be mimicked by exposure to threose, a metabolite generated by hyaluronan degradation, and was not linked to alteration in endogenous Wnt ligands expression. Rather, we observed that hyaluronan removal associated with disrupted primary cilia dynamics, with elongated cilium and higher proportions of preadipocytes that remained ciliated in hyaluronidase-treated conditions. Thus, our study points to a new link between ciliogenesis and hyaluronan impacting adipose tissue development.

Obesity-related parameters in carriers of some BDNF genetic variants may depend on daily dietary macronutrients intake.

Some common single-nucleotide polymorphisms of the brain-derived neurotrophic factor (BDNF) gene have been associated not only with the neurodegenerative diseases but also with some eating disorders. The aim of this study was to assess the possible differences in the obesity-related and glucose metabolism parameters between some BDNF genotypes', that may depend on the daily energy and macronutrients intake. In 484 adult participants we performed the anthropometric measurements, body composition analysis, and body fat distribution. The daily dietary intake was assessed using the 3-day food intake diaries. Blood glucose and insulin concentrations were measured at fasting and during oral glucose tolerance tests. Moreover, the visceral adipose tissue/subcutaneous adipose tissue (VAT/SAT) ratio and homeostatic model assessment of insulin resistance were calculated. We noted that participants carrying the GG genotype had lower skeletal muscle mass and fat free mass (FFM) when carbohydrate intake was > 48%, whereas they presented higher fat-free mass (FFM), and surprisingly higher total cholesterol and LDL-C concentrations when daily fiber intake was > 18 g. Moreover, in these subjects we noted higher waist circumference, BMI, and fasting glucose and insulin concentrations, when > 18% of total daily energy intake was delivered from proteins, and higher VAT content and HDL-C concentrations when > 30% of energy intake was derived from dietary fat. Our results suggest that glucose homeostasis and obesity-related parameters in carriers of some common variants of BDNF gene, especially in the GG (rs10835211) genotype carriers, may differ dependently on daily energy, dietary macronutrients and fiber intake.

Hyaluronan in Adipose Tissue, Metabolic Inflammation, and Diabetes: Innocent Bystander or Guilty Party?

Hyaluronic acid, or hyaluronan (HA), is a nonsulfated glucosaminoglycan that has long been recognized for its hydrophilic properties and is widely used as a dermal filler. Despite much attention given to the study of other extracellular matrix (ECM) components, in the field of ECM properties and their contribution to tissue fibroinflammation, little is known of HA's potential role in the extracellular milieu. However, recent studies suggest that it is involved in inflammatory response, diet-induced insulin resistance, adipogenesis, and autoimmunity in type 1 diabetes. Based on its unique physical property as a regulator of osmotic pressure, we emphasize underestimated implications in adipose tissue function, adipogenesis, and obesity-related dysfunction.

Importance of the Microenvironment and Mechanosensing in Adipose Tissue Biology.

The expansion of adipose tissue is an adaptive mechanism that increases nutrient buffering capacity in response to an overall positive energy balance. Over the course of expansion, the adipose microenvironment undergoes continual remodeling to maintain its structural and functional integrity. However, in the long run, adipose tissue remodeling, typically characterized by adipocyte hypertrophy, immune cells infiltration, fibrosis and changes in vascular architecture, generates mechanical stress on adipose cells. This mechanical stimulus is then transduced into a biochemical signal that alters adipose function through mechanotransduction. In this review, we describe the physical changes occurring during adipose tissue remodeling, and how they regulate adipose cell physiology and promote obesity-associated dysfunction in adipose tissue.

Resveratrol Relaxes Human Gastric Smooth Muscles Through High Conductance Calcium-Activated Potassium Channel in a Nitric Oxide-independent Manner.

Resveratrol, as a polyphenolic compound that can be isolated from plants, and also a component of red wine has broad beneficial pharmacological properties. The aim was to investigate the role of nitric oxide and potassium channels in resveratrol-induced relaxation of human gastric smooth muscle. Gastric tissues were obtained from patients who underwent sleeve gastrectomy for severe obesity (n = 10 aged 21-48; BMI 48.21 ± 1.14). The mechanical activity from the muscle strips was detected under isometric conditions as the response to increasing concentrations of resveratrol before and after different pharmacological treatments. Resveratrol caused an observable, dose-dependent gastric muscle relaxation. The maximal response caused by the highest concentration of resveratrol was 83.49 ± 2.85% (p < 0.0001) of the control. Preincubation with L-NNA, L-NAME, or ODQ did not prevent the resveratrol-induced relaxation. Apamin, glibenclamide, 4AP or tamoxifen, did not inhibit the relaxing effect of resveratrol, as well. In turn, blocking BKCa by TEA, iberiotoxin, or charybdotoxin resulted in inhibition of resveratrol-induced relaxation (91.08 ± 2.07, p < 0.05; 95.60 ± 1.52, p < 0.01 and 89.58 ± 1.98, p < 0.05, respectively). This study provides the first observation that the relaxant effects of resveratrol in human gastric muscle strips occur directly through BKCa channels and independently of nitric oxide signaling pathways. Furthermore, there is considerable potential for further extensive clinical studies with resveratrol as an effective new drug or health supplement to treat gastrointestinal dyspepsia and other gastric hypermotility disorders.

Phloroglucinol prevents albumin glycation as well as diminishes ROS production, glycooxidative damage, nitrosative stress and inflammation in hepatocytes treated with high glucose.

The treatment of diabetes mellitus aftermaths became one of medicine's most significant therapeutical and financial issues in the XXI century. Most of which are related to protein glycation and oxidative stress caused by long lasting periods of hyperglycemia. Thus, even within a venerable one, searching for new drugs, displaying anti-glycation and anti-oxidative properties seem useful as an additive therapy of diabetes. In this paper, we assessed the anti-glycating properties of phloroglucinol, a drug discovered in the XIX century and still used in many countries for its antispasmodic action. Herewith, we present its effect on protein glycation, glycoxidation, and oxidative damage in an albumin glycation/oxidation model and HepG2 cells treated with high glucose concentrations. The phloroglucinol showed the strongest and the widest protective effect within all analyzed antiglycating (aminoguanidine, pioglitazone) and anti-oxidative (vitamin C, GSH) agents. To the very best of our knowledge, this is the first study showing the properties of phloroglucinol in vitro what once is proven in other models might deepen its clinical applications.

Does weight loss after laparoscopic sleeve gastrectomy contribute to reduction in blood pressure?

INTRODUCTION: Obesity­related hypertension is a life threatening medical condition that significantly increases the risk of cardiovascular diseases and premature mortality. Effective treatment of obesity may be achieved by laparoscopic sleeve gastrectomy (LSG). This surgical method contributes not only to sustained weight loss but also to normalization of blood pressure. OBJECTIVES: To evaluate the effect of weight loss after LSG on partial or full control of blood pressure. PATIENTS AND METHODS: A retrospective analysis of medical and clinical data of 305 patients who had undergone LSG was performed. The bariatric effect of LSG was assessed by calculating percentage of total weight loss (%TWL), percentage of excess weight loss (%EWL), and percentage of excess BMI loss (%EBMIL). Blood pressure status after surgery was categorized as partial or full hypertension resolution. RESULTS: A total of 143 patients (46.9%) were diagnosed with hypertension preoperatively with median (IQR) hypertension duration of 7.52 (1.88-13.16) years. Hypertensive patients were older (49 vs 38.5 years) and had higher prevalence of coexisting diseases (type 2 diabetes, dyslipidemia, and obstructive sleep apnea) than patients with normal blood pressure. During 1­year follow up, 90 patients (63%) used lower doses of antihypertensive medications and 33 patients (23%) discontinued the therapy. Twelve months after the surgery, median (IQR) %TWL in the control group was 32.5% (28.1%-37.7%), while in the hypertensive group, 29.1% (25.9%-33.6%) (P <0.001); %EWL was 62.9% (53%-74.6%) and 54.8% (47.4%-68.2%), respectively (P = 0.001), and %EBMIL 73.9% (59.5%-91.2%) and 63% (55%-80.5%), respectively (P = 0.002). CONCLUSIONS: Laparoscopic sleeve gastrectomy is an effective method for the treatment of obesity­ related hypertension. However, weight loss induced by LSG does not affect the blood pressure status after the surgery.

Quercetin relaxes human gastric smooth muscles directly through ATP-sensitive potassium channels and not depending on the nitric oxide pathway.

BACKGROUND: Quercetin has recently become a remarkably popular subject of research due to its broad beneficial pharmacological properties. The goal of our study was to observe its effects on contractility of human gastric smooth muscles in reference to the NO pathway and direct influence of potassium channels. METHODS: Tissues were obtained from patients undergoing sleeve gastrectomy due to morbid obesity (n = 10 aged 24-56; BMI 47.16 ± 1.84). The following parameters were evaluated in the recordings: area under the curve (AUC), average baseline muscle tone, and relative change in muscle contraction. KEY RESULTS: Quercetin induced noticeable, dose-dependent relaxation of the carbachol treated gastric strips. The substantial effect was noted at concentrations higher than 10-7  mol/L and maximal at 10-4  mol/L (81.82 ± 3.32%; n = 10; p < 0.0001) of the control. Neither NOS blockers nor guanylyl cyclase blockers had inhibitory effects on the relaxation of strips induced by examined polyphenol. Glibenclamide inhibited the relaxing effect of quercetin, significant at concentrations higher than 5⋅10-5  mol/L. Preincubation with charybdotoxin or apamin extended the relaxing effect of quercetin (from 10-6  mol/L). Tamoxifen, in turn, significantly increased muscle relaxation at all quercetin concentrations. CONCLUSIONS & INFERENCES: In conclusion, the current study was the first to show that quercetin-induced relaxation of human gastric smooth muscle occurs directly through K+ATP channels and independently to NO pathways. The present results suggest that quercetin is a potential nutraceutical in the treatment of functional gastrointestinal dyspepsia and other minor gastric muscle motility disturbance.

Phloroglucinol Strengthens the Antioxidant Barrier and Reduces Oxidative/Nitrosative Stress in Nonalcoholic Fatty Liver Disease (NAFLD).

Nonalcoholic fatty liver disease (NAFLD) is one of the most commonly occurring diseases within western dietary patterns. Usually untreated, it may lead to type 2 diabetes mellitus (T2DM), steatohepatitis (NASH), and hepatocellular carcinoma (HCC). Besides its severe aftermath, up to now, there is no known therapeutic approach to this disease in everyday clinical practice. Most NAFLD patients are encouraged to do physical activities or diet change and remain without pharmacological treatment. In this study, we present phloroglucinol (PHG) as a novel and promising compound in NAFLD treatment. PHG significantly increased the level of enzymatic and nonenzymatic antioxidants both in palmitate and hydrogen peroxide-induced oxidative stress models. Strengthened antioxidative defense reduced the oxidative/nitrosative damage to cell proteins, lipids, and carbohydrates. Furthermore, PHG treatment reduced hepatic steatosis; lowered inflammatory markers, such as NF-κB or HIF-1α; and inhibited cell apoptosis. Moreover, PHG had a more comprehensive effect than other commonly used antioxidants: N-acetylcysteine (NAC) and α-lipoic acid (ALA), suggesting its clinical usability. Therefore, our paper supports the benefits of natural compounds as a therapeutical approach to NAFLD.

Impact of COVID-19 pandemic on bariatric patients in Podlaskie Voivodeship in Poland.

The research shows that despite the pandemic and higher risk of mortality and complications after SARS-CoV-2 infection, bariatric patients declare a high level of willingness to undergo the bariatric procedure, and the impact of COVID-19 pandemic does not play an important role in their decision-making process concerning the bariatric procedure. </br> </br> Due to the noticeable lifestyle changes during the pandemic such as greater food intake and decrease in physical activity among the bariatric patients, the process of qualification to the bariatric procedure should be conducted very meticulously and the recommended values for weight loss should be implemented to increase patients' motivation before and after the procedure. As the research shows, bariatric patients tend to neglect their strive for healthy lifestyle, even in the presence of the pandemic. Therefore, weight gain prior to the bariatric procedure can lead to more frequent complications during surgery and deterioration of the expected results of bariatric surgery. In conclusion, the group of bariatric patients is a high-risk group not only because of greater mortality due to COVID-19 infection, but also because they do not attach much importance to the external factors such as global pandemic.

The effect of enterolactone on liver lipid precursors of inflammation.

AIMS: The aim of this study was to assess the effects of enterolactone (ENL) on lipid fractions fatty acids composition affecting hepatocyte inflammation development. MAIN METHODS: The experiments were conducted in HepG2 cells incubated with ENL and/or palmitic acid (16 h). Intracellular contents of free fatty acids (FFA), di- (DAG) and tri- (TAG) acylglycerol as well as their fatty acids compositions were assessed by Gas-Liquid Chromatography. Moreover, the ω-6/ω-3 ratios in the above mentioned lipids fractions were estimated. The expression of proteins involved in eicosanoids and prostanoids production (COX-2, 15-LOX), inflammatory process (TNFα), as well as the proteins participating in the desaturation (SCD 1) and elongation (Elovl 3, Elovl 6) of fatty acids were evaluated by Western Blot. KEY FINDINGS: Enterolactone modified fatty acids composition in FFA, DAG and TAG fractions. In conjunction with lipid overload, it increased the content of ω-6 more than ω-3 PUFA. Moreover, it enhanced the expressions of Elovl 3, Elovl 6, COX-2 and TNFα, whereas it had no influence on SCD 1 and 15-LOX level. SIGNIFICANCE: Our study revealed that the supplementation with ENL affected intracellular hepatic composition of saturated as well as unsaturated fatty acids in each of the investigated lipid fractions. Based on the shift in the ω-6/ω-3 balance towards ω-6, as well as the increase in COX-2 and TNFα protein expressions, we may postulate a pro-inflammatory nature of the examined polyphenol. Moreover, our findings could prove to be useful in the future research in the topic of widespread diseases such as NASH.

The effect of enterolactone on sphingolipid pathway and hepatic insulin resistance development in HepG2 cells.

AIMS: Obesity and type 2 diabetes mellitus, correlate with increased tissue concentration of sphingolipids, which directly interfere with insulin signaling pathway. Phytoestrogens are a group of plant-derived compounds that have been studied in the case of metabolic disorders treatment. Therefore, the aim of this study was to ascertain whether enterolactone (ENL), a commonly known phytoestrogen, may affect sphingolipid metabolism and decrease hepatic insulin resistance development in a lipid overload state. MAIN METHODS: The study was conducted on HepG2 cells incubated with ENL and/or palmitic acid (PA) for 16 h. Intra- and extracellular sphingolipid concentrations were assessed by high performance liquid chromatography. The expression of sphingolipid pathway enzymes, apoptosis and insulin signaling pathway proteins and glucose metabolism regulators were evaluated by Western Blot. KEY FINDINGS: In HepG2 cells, a considerable augmentation of intracellular ceramide and sphingosine concentration in ENL with PA group were indicated with simultaneous increase in extracellular ceramide concentration. The ENL treatment increased expression of selected enzymes from de novo ceramide synthesis pathway with lower expression of ceramide transfer protein. We also observed a decreased expression of insulin-stimulated phosphorylation of AKT and AMPK after exposure to ENL with PA. Our research demonstrated that ENL with PA resulted in an increased expression of caspase-3. SIGNIFICANCE: Enterolactone, in a higher fatty acids availability, led to the development of hepatic IR in HepG2 cells. This phenomenon may be the result of elevated intracellular ceramide accumulation caused by increased de novo synthesis pathway what led to enhanced apoptosis of HepG2 cells.

Influence of Resveratrol on Sphingolipid Metabolism in Hepatocellular Carcinoma Cells in Lipid Overload State.

BACKGROUND: Obesity is characterized by increased long chain fatty acids (LCFA) uptake and impaired lipid metabolism in hepatocytes. Consequently, an enhanced intracellular lipid content, including sphingolipids, may lead to lipotoxicity. It is believed that resveratrol (RSV), one of the most extensively studied plant-derived polyphenols, and its interaction with sphingolipid metabolism may constitute one of the major therapeutic targets for cancer and metabolic diseases treatment. OBJECTIVE: The aim of this study was to ascertain, whether resveratrol may affect sphingolipid metabolic pathways, enzymes and transporters in a lipid overload state. METHODS: The experiments were conducted on hepatocellular carcinoma cells (HepG2) incubated with RSV and/or Palmitic Acid (PA) at the concentration of 0.5 mM and 50 µM, respectively for 16h. Intra- and extracellular sphingolipid concentrations were assessed by high-performance liquid chromatography and gas liquid chromatography. Moreover, the expression of caspase 3, selected fatty acid transporters and sphingolipid metabolism pathway proteins were estimated by Western Blot. RESULTS: RSV alone and together with PA significantly increased the intracellular concentration of ceramide, sphinganine and sphingosine as well as the expression of enzymes related to de novo ceramide synthesis pathway. Moreover, in our study, we observed augmented ceramide and sphingomyelin efflux into the incubation media in these groups. In addition, RSV substantially reduced intracellular triacylglycerols accumulation in lipid overload conditions. CONCLUSION: The above-mentioned findings suggest that RSV, at least partially, demonstrates a potential protective effect on HepG2 cells in a lipid overload state.

Does the enterolactone (ENL) affect fatty acid transporters and lipid metabolism in liver?

BACKGROUND: NAFLD as a result of inappropriate diet and obesity, may progress to sever conditions such as: type 2 diabetes mellitus or steatohepatitis, and has recently become a prevalent topic of numerous investigations. Due to its dangerous aftermaths, finding new substances, such as polyphenols and their derivatives, which might reduce liver steatosis is the main target of research into NAFLD treatment. Hence, the aim of the present study was to evaluate the effect(s) of enterolactone (ENL), a metabolite of secoisolariciresinol (SECO), on lipid metabolism together with changes in the expression of fatty acid transporters in fatty liver. METHODS: The experiments were conducted on HepG2 cells incubated with either ENL and/or palmitic acid during 16 h exposure. The expression of selected fatty acid transport proteins: FATP2, FATP5, CD36, FABPpm, ABCA1, MTP, ACBP and L-FABP, as well as the proteins directly involved in lipogenesis (FAS), oxidation pathway (CPT 1), and lipid metabolism (PPARα, LXR, SREBP1c, pAMPK) was estimated by Western Blot. Intra and extracellular lipid contents were assessed by Gas-Liquid Chromatography. The data was analyzed with two-way analysis of variance (ANOVA), and results were considered to be statistically significant at p ≤ 0.05. RESULTS: ENL stimulated extracellular efflux of free fatty acids (FFA) and triacylglicerols (TAG) to the medium, while, it had no influence on FATP-family mediated intracellular fatty acid uptake. Moreover, ENL decreased the expression of CPT 1, pAMPK, PPARα, increased SREBP1c and had no effect on LXR, and FAS content. CONCLUSIONS: The findings of our study demonstrate that ENL had opposite effect on liver steatosis in comparison with other polyphenols what suggests that it may be an inactive metabolite. ENL did not affect significantly the intracellular accumulation of FFA, DAG and TAG, yet it promoted their extracellular efflux. Furthermore, it inhibited ß-oxydation and intracellular lipid metabolism what may contribute to the progression of NAFLD.

Alternative treatment methods attenuate the development of NAFLD: A review of resveratrol molecular mechanisms and clinical trials.

Nonalcoholic fatty liver disease (NAFLD) is considered to be one of the most common liver pathologies that occur widely among societies with a predominance of the Western dietary pattern. NAFLD may progress from hepatic steatosis to nonalcoholic steatohepatitis (NASH), subsequently leading to cirrhosis and becoming a major cause of hepatocellular carcinoma. Thus its prevention and therapy play an important role in hepatology. To our knowledge, there is no effective treatment for patients with NAFLD. The aim of this review was to summarize the results of recent alternative treatment studies conducted both on cell cultures and in vivo that concern molecular effects of resveratrol (3,5,4'-trihydroxystilbene) in the treatment of NAFLD. The precise metabolism, pharmacology, and clinical trials with different concentrations of resveratrol were described. The review also presents a brief summary of other alternative treatment methods of NAFLD and their mechanisms compared with current clinical understanding.