Impact of Smoking on Salivary Lipid Profile and Oxidative Stress in Young Adults: A Comparative Analysis between Traditional Cigarettes, E-Cigarettes, and Heat-Not-Burn Products.

BACKGROUND Smoking nicotine is considered to be one of the most harmful addictions, leading to the development of a number of health complications, including many pathologies in the oral cavity. The aim of this study was to examine the effect of smoking traditional cigarettes, e-cigarettes, and heat-not-burn products on profiles of salivary lipids and lipid peroxidation products in the unstimulated and stimulated saliva of healthy young adults with a smoking habit of up to 3 years. MATERIAL AND METHODS We enrolled 3 groups of 25 smoking patients each and a control group matched for age, gender, and oral status. In saliva collected from patients from the study groups and participants from the control group, the concentrations of sphingolipids: sphingosine, sphinganine, sphingosine-1-phosphate, ceramides, and salivary lipid peroxidation products - malondialdehyde (MDA) and 4-hydroxynonenal (HNE) - were measured. The normality of distribution was assessed using the Shapiro-Wilk test. For comparison of the results, one-way analysis of variance (ANOVA) followed by post hoc Tukey test was used. RESULTS We demonstrated that each type of smoking causes a decrease in the concentration of salivary lipids, and there was an increased concentration of salivary MDA and 4-HNE. CONCLUSIONS Smoking in the initial period of addiction leads to an increase in the concentration of lipid peroxidation products through increased oxidative stress, leading to disturbance of the lipid balance of the oral cavity (eg, due to damage to cell membranes).

Diverse Sphingolipid Profiles in Rectal and Colon Cancer.

Colorectal cancer is a heterogenous group of neoplasms showing a variety of clinical and pathological features depending on their anatomical location. Sphingolipids are involved in the formation and progression of cancers, and their changes are an important part of the abnormalities observed during carcinogenesis. Because the course of rectal and colonic cancer differs, the aim of the study was to assess whether the sphingolipid profile is also different in tumors of these two regions. Using a combination of ultra-high-performance liquid chromatography combined with triple quadrupole mass spectrometry, differences in the amounts of cellular sphingolipids were found in colorectal cancer. Sphingosine content was higher in rectal cancer than in adjacent healthy tissue, while the content of two ceramides (C18:0-Cer and C20:0-Cer) was lower. In colon cancer, a higher content of sphingosine, sphinganine, sphingosine-1-phosphate, and two ceramides (C14:0-Cer and C24:0-Cer) was found compared to healthy tissue, but there was no decrease in the amount of any of the assessed sphingolipids. In rectal cancer, the content of sphinganine and three ceramides (C16:0-Cer, C22:0-Cer, C24:0-Cer), as well as the entire pool of ceramides, was significantly lower compared to colon cancer. The S1P/Cer ratio in rectal cancer (S1P/C18:1-Cer, S1P/C20:0-Cer, S1P/C22:0-Cer, S1P/C24:1-Cer) and in colon cancer (S1P/C18:0-Cer, S1P/C18:1-Cer, S1P/C20:0-Cer) was higher than in adjacent healthy tissue and did not differ between the two sites (rectal cancer vs. colonic cancer). It seems that the development of colorectal cancer is accompanied by complex changes in the metabolism of sphingolipids, causing not only qualitative shifts in the ceramide pool of cancer tissue but also quantitative disturbances, depending on the location of the primary tumor.

The Effect of Silencing the Genes Responsible for the Level of Sphingosine-1-phosphate on the Apoptosis of Colon Cancer Cells.

Sphingosine-1-phosphate (S1P) and ceramides (Cer) are engaged in key events of signal transduction, but their involvement in the pathogenesis of colorectal cancer is not conclusive. The aim of our study was to investigate how the modulation of sphingolipid metabolism through the silencing of the genes involved in the formation (SPHK1) and degradation (SGPL1) of sphingosine-1-phosphate would affect the sphingolipid profile and apoptosis of HCT-116 human colorectal cancer cells. Silencing of SPHK1 expression decreased S1P content in HCT-116 cells, which was accompanied by an elevation in sphingosine, C18:0-Cer, and C18:1-Cer, increase in the expression and activation of Caspase-3 and -9, and augmentation of apoptosis. Interestingly, silencing of SGLP1 expression increased cellular content of both the S1P and Cer (C16:0-; C18:0-; C18:1-; C20:0-; and C22:0-Cer), yet inhibited activation of Caspase-3 and upregulated protein expression of Cathepsin-D. The above findings suggest that modulation of the S1P level and S1P/Cer ratio regulates both cellular apoptosis and CRC metastasis through Cathepsin-D modulation. The cellular ratio of S1P/Cer seems to be a crucial component of the above mechanism.

The Role of Obesity, Inflammation and Sphingolipids in the Development of an Abdominal Aortic Aneurysm.

Abdominal aortic aneurysm (AAA) is a local dilatation of the vessel equal to or exceeding 3 cm. It is a disease with a long preclinical period commonly without any symptoms in its initial stage. Undiagnosed for years, aneurysm often leads to death due to vessel rupture. The basis of AAA pathogenesis is inflammation, which is often associated with the excess of adipose tissue, especially perivascular adipose tissue, which synthesizes adipocytokines that exert a significant influence on the formation of aneurysms. Pro-inflammatory cytokines such as resistin, leptin, and TNFα have been shown to induce changes leading to the formation of aneurysms, while adiponectin is the only known compound that is secreted by adipose tissue and limits the development of aneurysms. However, in obesity, adiponectin levels decline. Moreover, inflammation is associated with an increase in the amount of macrophages infiltrating adipose tissue, which are the source of matrix metalloproteinases (MMP) involved in the degradation of the extracellular matrix, which are an important factor in the formation of aneurysms. In addition, an excess of body fat is associated with altered sphingolipid metabolism. It has been shown that among sphingolipids, there are compounds that play an opposite role in the cell: ceramide is a pro-apoptotic compound that mediates the development of inflammation, while sphingosine-1-phosphate exerts pro-proliferative and anti-inflammatory effects. It has been shown that the increase in the level of ceramide is associated with a decrease in the concentration of adiponectin, an increase in the concentration of TNFα, MMP-9 and reactive oxygen species (which contribute to the apoptosis of vascular smooth muscle cell). The available data indicate a potential relationship between obesity, inflammation and disturbed sphingolipid metabolism with the formation of aneurysms; therefore, the aim of this study was to systematize the current knowledge on the role of these factors in the pathogenesis of abdominal aortic aneurysm.

The development of cigarette smoke induced chronic pancreatitis in mice is associated with increased expression of K-Ras and NF-κB.

INTRODUCTION AND OBJECTIVE: Epidemiological studies have demonstrated a strong association between cigarette smoking (CS) and chronic pancreatitis (CP); however, the exact mechanisms of this phenomenon remains unknown. The authors have previously shown that increased Ras expression activates the NF-κB mediated pathway and promotes development of CP. However, it is unclear whether a similar phenomenon occurs in CS-induced CP. Therefore, the aim of the study was to determine whether CS increases the expression of K-Ras, and promotes the development of CP in mice exposed to repeated episodes of acute pancreatitis (AP). MATERIAL AND METHODS: C57BL6/cmdb mice were exposed to CS or a sham treatment for 12 weeks. After one week of exposure, half of the animals from both groups were additionally subjected to repeated cerulein treatment (once a week, for 10 consecutive weeks) to mimic recurrent episodes of AP. Extension of pancreatic damage was determined histologically by H&E and Trichrome staining. The expression of K-Ras protein and downstream components (NF-κB, Cox-2, TGF-ß) was evaluated by immunohistochemistry. RESULTS: C57BL6/cmdb mice exposed to CS or cerulein alone did not develop any chronic pancreatic damage. However, concomitant treatment with both of these agents caused focal acinar atrophy, with slight intralobular and perivascular areas of fibrosis, and inflammatory cells infiltration resembling mild CP. Moreover, immunohistochemistry examinations revealed increased pancreatic expression of K-Ras and NF-κB only in mice treated both with CS and cerulein. CONCLUSIONS: CS promotes development of CP in mice exposed to repeated episodes of AP. This process may be, at least partially, related to increased expression of K-Ras and NF-κB protein.

Extreme duration exercise affects old and younger men differently.

AIM & METHODS: Extreme endurance exercise provides a valuable research model for understanding the adaptive metabolic response of older and younger individuals to intense physical activity. Here, we compare a wide range of metabolic and physiologic parameters in two cohorts of seven trained men, age 30 ± 5 years or age 65 ± 6 years, before and after the participants travelled ≈3000 km by bicycle over 15 days. RESULTS: Over the 15-day exercise intervention, participants lost 2-3 kg fat mass with no significant change in body weight. V̇O2 max did not change in younger cyclists, but decreased (p = 0.06) in the older cohort. The resting plasma FFA concentration decreased markedly in both groups, and plasma glucose increased in the younger group. In the older cohort, plasma LDL-cholesterol and plasma triglyceride decreased. In skeletal muscle, fat transporters CD36 and FABPm remained unchanged. The glucose handling proteins GLUT4 and SNAP23 increased in both groups. Mitochondrial ROS production decreased in both groups, and ADP sensitivity increased in skeletal muscle in the older but not in the younger cohort. CONCLUSION: In summary, these data suggest that older but not younger individuals experience a negative adaptive response affecting cardiovascular function in response to extreme endurance exercise, while a positive response to the same exercise intervention is observed in peripheral tissues in younger and older men. The results also suggest that the adaptive thresholds differ in younger and old men, and this difference primarily affects central cardiovascular functions in older men after extreme endurance exercise.

Blood bioactive sphingolipids in patients with advanced serous epithelial ovarian cancer - mass spectrometry analysis.

INTRODUCTION: Due to the lack of highly specific and sensitive methods for diagnosing ovarian cancer at advanced stages (according to the International Federation of Gynecology and Obstetrics (FIGO) classification stage III-IV), new noninvasive biomarkers are urgently needed. This study aims to investigate how the levels of plasma bioactive sphingolipids (ceramides, sphingosine-1-phosphate, sphingosine and sphinganine) are altered in serum, erythrocytes and platelets of patients with advanced serous ovarian cancer. MATERIAL AND METHODS: A total of 135 patients with advanced serous ovarian cancer and 159 women with normal ovarian morphology were enrolled. Plasma levels of sphingosine, sphingosine-1-phosphate, sphinganine, ceramide C14:0-Cer, C16:0-Cer, C18:1-Cer, C18:0-Cer, C20:0-Cer, C22:0-Cer, C24:1-Cer and C24:0-Cer were assessed by LC/MS/MS. RESULTS: Plasma concentrations of C16-Cer, C18:1-Cer and C18-Cer were significantly higher in the advanced ovarian cancer group than in the control group (1.5-fold, p = 0.021; 1.8-fold, p = 0.036 and 1.5-fold, p = 0.031, respectively). Plasma concentration of C18:1-Cer was significantly higher in erythrocytes of women with advanced serous cancer compared to the control group (p = 0.027). Plasma C16-Cer and C18:1-Cer levels and erythrocyte C18:1-Cer levels were able to distinguish patients with moderate/severe serous ovarian cancer from patients with mild ovarian cancer (AUC: 0.86, 0.898, 0.795, respectively). Plasma concentrations of C16, C18.1 and C18 significantly correlated with FIGO staging (p = 0.001, p = 0.024 and p = 0.005), and grading (p = 0.021, p = 0.021 and p = 0.033). CONCLUSIONS: Plasma concentrations of C16, C18.1 and C18 correlated with the progression of ovarian cancer (FIGO staging and grading). Plasma levels of C16-Cer and C18:1-Cer and erythrocyte C18:1-Cer levels could be used to distinguish patients with advanced serous ovarian cancer.

The influence of patient's age on metabolic and bariatric results of laparoscopic sleeve gastrectomy in 2-year observation.

BACKGROUND: The incidence of obesity has been constantly growing and bariatric procedures are considered to be the most effective treatment solution for morbidly obese patients. The results of laparoscopic sleeve gastrectomy (LSG) may differ depending on patient's age, gender, preoperative body mass index (BMI) and physical activity. METHODS: The aim of this study was to evaluate age-related differences in the outcome of LSG in terms of weight loss parameters, lipid and carbohydrate profile. The retrospective analysis of 555 patients who had undergone LSG was performed to compare the metabolic outcomes of surgery in individuals < 45 and ≥ 45 years old. Evaluation of weight loss parameters along with selected laboratory data was performed to demonstrate the results of LSG in 2 years follow-up. RESULTS: Overall, 238 males and 317 females (43%/57%) with median age of 43 years and median preoperative BMI of 46.41 (42.06-51.02) kg/m2 were analyzed. Patients in both groups presented significant weight loss at 24 months after the surgery with comparable percentage of total weight loss (40.95% in < 45 years old group and 40.44% in ≥ 45 years old group). The percentage of excess weight loss (78.52% vs. 74.53%) and percentage of excess BMI loss (91.95% vs. 88.01%) were higher in patients < 45 years old. However, the differences were not statistically significant (p = 0.662, p = 0.788 respectively). Patients under 45 years old experienced faster decrease in fasting glucose level that was observed after only 3 months (109 mg/dl to 95 mg/dl in < 45 years old group vs. 103.5 mg/dl to 99.5 mg/dl in ≥ 45 years old group, p < 0.001). Both groups presented improvement of lipid parameters during the observation. However, patients < 45 years old achieved lower values of LDL at 3 and 12 months follow-up (115 mg/dl vs. 126 mg/dl, p = 0.010; 114.8 mg/dl vs. 122 mg/dl, p = 0.002). Younger group of patients also showed superior improvement of triglycerides level. CONCLUSIONS: LSG results in significant weight loss in all patients regardless age. In turn, superior and faster improvement in lipid and carbohydrate profile is achieved in patients under 45 years old.

Sphingolipid Analysis Indicate Lactosylceramide as a Potential Biomarker of Inflammatory Bowel Disease in Children.

An altered ceramide composition in patients with inflammatory bowel disease (IBD) has been reported recently. The aim of this study was to evaluate the concentrations of sphingolipids in the serum of treatment-naive children with newly diagnosed IBD and to determine the diagnostic value of the tested lipids in pediatric IBD. The concentrations of sphingolipids in serum samples were evaluated using a quantitative method, an ultra-high-performance liquid chromatography-tandem mass spectrometry in children with Crohn's disease (CD) (n=34), ulcerative colitis (UC) (n = 39), and controls (Ctr) (n = 24). Among the study groups, the most significant differences in concentrations were noted for C16:0-LacCer, especially in children with CD compared to Ctr or even to UC. Additionally, the relevant increase in C20:0-Cer and C18:1-Cer concentrations were detected in both IBD groups compared to Ctr. The enhanced C24:0-Cer level was observed only in UC, while C18:0-Cer only in the CD group. The highest area under the curve (AUC), specificity, and sensitivity were determined for C16:0-LacCer in CD diagnosis. Our results suggest that the serum LacC16-Cer may be a potential biomarker that distinguishes children with IBD from healthy controls and differentiates IBD subtypes. In addition, C20:0-Cer and C18:0-Cer levels also seem to be closely connected with IBD.

Obesity, Bioactive Lipids, and Adipose Tissue Inflammation in Insulin Resistance.

Obesity is a major risk factor for the development of insulin resistance and type 2 diabetes. The exact mechanism by which adipose tissue induces insulin resistance is still unclear. It has been demonstrated that obesity is associated with the adipocyte dysfunction, macrophage infiltration, and low-grade inflammation, which probably contributes to the induction of insulin resistance. Adipose tissue synthesizes and secretes numerous bioactive molecules, namely adipokines and cytokines, which affect the metabolism of both lipids and glucose. Disorders in the synthesis of adipokines and cytokines that occur in obesity lead to changes in lipid and carbohydrates metabolism and, as a consequence, may lead to insulin resistance and type 2 diabetes. Obesity is also associated with the accumulation of lipids. A special group of lipids that are able to regulate the activity of intracellular enzymes are biologically active lipids: long-chain acyl-CoAs, ceramides, and diacylglycerols. According to the latest data, the accumulation of these lipids in adipocytes is probably related to the development of insulin resistance. Recent studies indicate that the accumulation of biologically active lipids in adipose tissue may regulate the synthesis/secretion of adipokines and proinflammatory cytokines. Although studies have revealed that inflammation caused by excessive fat accumulation and abnormalities in lipid metabolism can contribute to the development of obesity-related insulin resistance, further research is needed to determine the exact mechanism by which obesity-related insulin resistance is induced.

Ceramides Profile Identifies Patients with More Advanced Stages of Colorectal Cancer.

Much attention is paid to different sphingolipid pathways because of their possible use in diagnostics and treatment. However, the activity status and significance of ceramide pathways in colorectal cancer are still unclear. We analyzed colorectal cancer patients to evaluate sphingolipid profiles in the blood, colorectal cancer (CRC) tissues, and healthy surrounding colorectal tissues of the same patient, simultaneously, using liquid chromatography coupled with triple quadrupole mass spectrometry. Furthermore, we measured protein expression of de novo ceramide synthesis enzymes and mitochondrial markers in tissues using western blot. We confirmed the different sphingolipid contents in colorectal cancer tissue compared to healthy surrounding tissues. Furthermore, we showed changed amounts of several ceramides in more advanced colorectal cancer tissue and found a prominently higher circulating level of several of them. Moreover, we observed a relationship between the amounts of some ceramide species in colorectal cancer tissue and plasma depending on the stage of colorectal cancer according to TNM (tumors, nodes, metastasis) classification. We think that the combined measurement of several ceramide concentrations in plasma can help distinguish early-stage lesions from advanced colorectal cancer and can help produce a screening test to detect early colorectal cancer.

Laparoscopic sleeve gastrectomy: a study of efficiency in treatment of metabolic syndrome components, comorbidities and influence on certain biochemical markers.

INTRODUCTION: The worldwide outbreak of morbid obesity forced contemporary medicine to adopt a multidisciplinary approach, which led to the description of metabolic syndrome (MS): a disease with self-aggravating components and one of the most important causes of morbidity and mortality. The need for therapeutic methods provoked development of metabolic surgery, which nowadays give possibilities for safe and effective treatment of all MS aspects simultaneously and improves many obesity-related comorbidities. AIM: To assess the laparoscopic sleeve gastrectomy (LSG) procedure's efficiency in resolving MS components, treating comorbidities and to analyze the influence on certain biochemical markers in 1-year follow-up. MATERIAL AND METHODS: The retrospective cohort study of 211 patients after an LSG operation relied on statistical analysis of clinical data collected prospectively in follow-up visits. All applicable guidelines and bioethical recommendations were respected in this study. RESULTS: Assessment of bariatric efficiency proved the LSG operation to be effective in inducing significant weight loss and treating obesity. Analysis on the influence on MS components, such as non-insulin dependent diabetes (NIDDM), arterial hypertension (AH) and dyslipidemia, showed substantial improvement in all observed cases of these diseases. In the present study, follow-up also proved a partial remission inducing effect of this bariatric operation in many comorbidities, especially in chronic obstructive pulmonary disease, obstructive sleep apnea, peptic ulcer disease and depression. A desirable reduction in creatinine, C-reactive protein, uric acid, alanine aminotransferase, asparagine aminotransferase, γ-glutamyltransferase serum levels has also been observed during the follow-up. CONCLUSIONS: The LSG is an effective method of treatment in all areas of metabolic syndrome, provides a significant positive clinical outcome in obesity-related comorbidities and induces desirable changes in inflammatory, kidney and liver related biomarkers.

Gender-related metabolic outcomes of laparoscopic sleeve gastrectomy in 6-month follow-up.

INTRODUCTION: Laparoscopic sleeve gastrectomy (LSG) is recently a leading method in surgical treatment of morbid obesity. The metabolic outcome of intervention may be a result of many factors such as age, gender, preoperative weight loss and dietary restrictions. AIM: To evaluate gender-related differences in the results of LSG in 6-month follow-up. MATERIAL AND METHODS: The study included 101 patients who underwent LSG at the University Clinical Hospital of Bialystok. Patients were divided and analyzed in 2 groups: males (n = 48) and females (n = 53). The primary analysis included the influence of gender on postoperative weight loss calculated using the percentage of excess weight loss (%EWL) and excess BMI loss (%EBMIL). For secondary outcomes the levels of glucose, insulin, glycated hemoglobin, aspartate transaminase, alanine transaminase, total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides and C-reactive protein were analyzed. RESULTS: A significant influence of patients' gender was proved for both %EWL (p = 0.026) and %EBMIL (p = 0.001). Females had significantly higher %EWL in 6-month follow-up than males (p = 0.0034). The analysis also showed significantly higher %EBMIL for women at 3 and 6 months observation (p = 0.022 and p < 0.001 respectively). CONCLUSIONS: Laparoscopic sleeve gastrectomy is an effective method of obesity treatment especially in terms of postoperative weight loss. Females seem to benefit more from the procedure when analyzing the parameters of body mass reduction. However, further research is needed to provide strong evidence of an association between gender and the results of LSG.

High-Fat Diet Affects Ceramide Content, Disturbs Mitochondrial Redox Balance, and Induces Apoptosis in the Submandibular Glands of Mice.

This is the first study to investigate the relationship between ceramides, the mitochondrial respiratory system, oxidative stress, inflammation, and apoptosis in the submandibular gland mitochondria of mice with insulin resistance (IR). The experiment was conducted on 20 male C57BL/6 mice divided into two equal groups: animals fed a high-fat diet (HFD; 60 kcal% fat) and animals fed a standard diet (10 kcal% fat). We have shown that feeding mice HFD induces systemic IR. We noticed that HFD feeding was accompanied by a significant increase in ceramide production (C18 1Cer, C18 Cer, C22 Cer, C24 1Cer, C24 Cer), higher activity of pro-oxidant enzymes (NADPH oxidase and xanthine oxidase), and weakened functioning of mitochondrial complexes in the submandibular glands of IR mice. In this group, we also observed a decrease in catalase and peroxidase activities, glutathione concentration, redox status, increased concentration of protein (advanced glycation end products, advanced oxidation protein products) and lipid (malondialdehyde, lipid hydroperoxide) peroxidation products, and enhanced production of tumor necrosis factor alpha (TNFα) and interleukin 2 (IL-2) as well as pro-apoptotic Bax in the submandibular gland mitochondria. In summary, HFD impairs salivary redox homeostasis and is responsible for enhanced oxidative damage and apoptosis in the submandibular gland mitochondria. The accumulation of some ceramides could boost free radical formation by affecting pro-oxidant enzymes and the mitochondrial respiratory chain.

Ceramide Content in Liver Increases Along with Insulin Resistance in Obese Patients.

The liver plays a central role in the glucose and lipid metabolism. Studies performed on animal models have shown an important role of lipid accumulation in the induction of insulin resistance. We sought to explain whether in obese humans, the insulin resistance is associated with hepatic ceramide accumulation. The experiments were conducted on obese men and women. Each gender was divided into three groups: Normal glucose tolerance group (NGT), Impaired glucose tolerance group (IGT), and Type 2 diabetic subjects (T2D). Ceramide (Cer) content was analyzed with the use of LC/MS/MS. An oral glucose tolerance test (OGTT), glycosylated hemoglobin (HbA1c), percentage body fat (FAT%), and body mass index (BMI) was also measured. Total hepatic ceramide was significantly higher in T2D females as compared to NGT females (p < 0.05), whereas in males, total ceramide was significantly higher in IGT and T2D as compared to NGT (p < 0.05). In both, men and women, the highest increase in T2D subjects, was observed in C16:0-Cer, C18:0:-Cer, C22:0-Cer, and C24:0-Cer (p < 0.05) as compared to NGT group. Interestingly, glucose (at 0' and at 120' in OGTT) and HbA1c positively correlated with the ceramide species that most increased in T2D patients (C16:0-Cer, C18:0-Cer, C22:0-Cer, and C24:0-Cer). In men glucose and HbA1c significantly correlated with only C22:0-Cer. This is one of the few studies comparing hepatic ceramide content in severely obese patients. We found that, ceramide content increased in diabetic patients, both in men and women, and the content of ceramide correlated with glycemic parameters. These data indicate ceramide contribution to the induction of hepatic insulin resistance.

Metformin treatment affects adipocytokine secretion and lipid composition in adipose tissues of diet-induced insulin-resistant rats.

OBJECTIVES: Adipose tissue plays a central role in the pathogenesis of insulin resistance (IR) and type 2 diabetes. However, the molecular changes that promote these diseases are not completely understood. Several studies demonstrated that ceramide (Cer) and diacylglycerol (DAG) accumulation in muscle is associated with IR. The aim of this study was to explain whether a high-fat diet (HFD) leads to bioactive lipid accumulation in adipose tissue and how metformin affects the lipid content in adipocytes and the concentration of plasma adipocytokines. METHODS: The experiments were conducted on male Wistar rats divided into three groups: control, HFD-fed, and HFD-fed and treated with metformin. Cer and DAGs were analyzed by liquid chromatography tandem mass spectrometry. Phosphorylation of hormone-sensitive lipase (HSL) was analyzed by Western blot. Oral glucose tolerance and insulin tolerance tests were also performed. Plasma adiponectin and tumor necrosis factor (TNF)-α concentration were measured by enzyme-linked immunosorbent assay. RESULTS: HFD induced IR and elevated DAGs and Cer content in subcutaneous and visceral adipose tissues, which was accompanied by an increased phosphorylation of HSL. Metformin improved insulin sensitivity, decreased Cer and DAG levels, and attenuated the phosphorylation of HSL in both fat depots. Furthermore, we observed a strong correlation between adiponectin (negative) and TNF-α (positive) and bioactive lipids in both fat tissues. CONCLUSIONS: These results indicated that bioactive lipids accumulation in adipose tissue influences the induction of IR and, at least in part, answered the question of what the insulin-sensitizing effect of metformin at the level of adipose tissue is.

The Relationship between the Concentration of Cathepsin A, D, and E and the Concentration of Copper and Zinc, and the Size of the Aneurysmal Enlargement in the Wall of the Abdominal Aortic Aneurysm.

BACKGROUND: Despite advances in diagnostics and treatment, aortic aneurysms are an important clinical problem, mainly due to the accompanying complications that may lead to direct loss of life, also the number of diagnosed and operated aneurysms is constantly increasing. The aim of this study is to determine the relationship between the concentration of lysosomal peptidases cathepsin A, D, and E in the wall of the abdominal aortic aneurysm and the concentration of copper and zinc, and the size of the aneurysm widening in the wall of the abdominal aortic aneurysm. METHODS: The study included 27 patients with abdominal aortic aneurysm from the Department of Vascular Surgery and Transplantation of the University Clinical Hospital in Bialystok. The research material was the wall of the abdominal aortic aneurysm collected intraoperatively. The control material consisted of fragments of the abdominal aorta obtained from organ donors for transplantation. The concentration of cathepsin A, D, and E was determined using enzyme-linked immunosorbent assays. Concentrations of copper and zinc were determined by flame atomic absorption spectrometry after prior mineralization of the samples. All patients were interviewed and asked about basic demographic data, comorbidities, and risk factors for cardiovascular disease to which they were exposed in the past. The statistical analysis was performed using Statistica 10 statistical package. Mann-Whitney U-tests were used and also Spearman's r correlation assuming a significance level of P < 0.05. RESULTS: The concentration of cathepsin A, D, and E was higher in the aortic wall altered by the aneurysm than in the wall of the control aorta (P < 0.05). The analysis of the data showed that there was a positive correlation between the concentration of cathepsin A and D and the width of the aneurysmal widening (r = 0.699 and 0.750, respectively). There was no correlation between cathepsin E concentration and aneurysm width. CONCLUSIONS: The higher contents of cathepsin A, D, and E in the wall of the aortic aneurysm than in the normal aortic wall, as well as a positive correlation between the concentration of cathepsin A and D and the width of the aneurysmal widening, allow to assume the participation of these enzymes in the pathogenesis of the aneurysm.

Inhibition of Ceramide De Novo Synthesis Affects Adipocytokine Secretion and Improves Systemic and Adipose Tissue Insulin Sensitivity.

Ceramide accumulation in muscle and in liver is implicated in the induction of insulin resistance. Much less in known about the role of ceramide in adipose tissue. The aim of the present study was to elucidate the role of ceramide in adipose tissue and to clarify whether lipids participate in the regulation of adipocytokine secretion. The experiments were performed on male Wistar rats divided into three groups: 1. Control, 2. fed high fat diet (HFD), and 3. fed HFD and treated with myriocin. Ceramide (Cer) and diacylglycerol (DAG) content were analyzed by LC/MS/MS. Hormone sensitive lipase (HSL) phosphorylation was analyzed by Western Blot. Plasma adiponectin and tumor necrosis factor alpha (TNF-α) concentration were measured by enzyme-linked immunosorbent assay. An oral glucose tolerance test (OGTT) and insulin tolerance test (ITT) was also performed. In HFD group, total DAG and Cer content was elevated in both subcutaneous and visceral adipose tissue, which was accompanied by increased glucose, insulin, and HOMA-IR value. Myriocin treatment restored HOMA-IR as well as glucose and insulin concentration to control values. Moreover, myriocin decreased not only Cer, but also DAG levels in both fat depots. Furthermore, we observed a strong correlation between adiponectin (negative) and TNF-α (positive) and Cer in both fat tissues, which suggests that Cer is involved in the regulation of adipocytokine secretion.

Protective role of the ELOVL2/docosahexaenoic acid axis in glucolipotoxicity-induced apoptosis in rodent beta cells and human islets.

AIMS/HYPOTHESIS: Dietary n-3 polyunsaturated fatty acids, especially docosahexaenoic acid (DHA), are known to influence glucose homeostasis. We recently showed that Elovl2 expression in beta cells, which regulates synthesis of endogenous DHA, was associated with glucose tolerance and played a key role in insulin secretion. The present study aimed to examine the role of the very long chain fatty acid elongase 2 (ELOVL2)/DHA axis on the adverse effects of palmitate with high glucose, a condition defined as glucolipotoxicity, on beta cells. METHODS: We detected ELOVL2 in INS-1 beta cells and mouse and human islets using quantitative PCR and western blotting. Downregulation and adenoviral overexpression of Elovl2 was carried out in beta cells. Ceramide and diacylglycerol levels were determined by radio-enzymatic assay and lipidomics. Apoptosis was quantified using caspase-3 assays and poly (ADP-ribose) polymerase cleavage. Palmitate oxidation and esterification were determined by [U-14C]palmitate labelling. RESULTS: We found that glucolipotoxicity decreased ELOVL2 content in rodent and human beta cells. Downregulation of ELOVL2 drastically potentiated beta cell apoptosis induced by glucolipotoxicity, whereas adenoviral Elovl2 overexpression and supplementation with DHA partially inhibited glucolipotoxicity-induced cell death in rodent and human beta cells. Inhibition of beta cell apoptosis by the ELOVL2/DHA axis was associated with a decrease in ceramide accumulation. However, the ELOVL2/DHA axis was unable to directly alter ceramide synthesis or metabolism. By contrast, DHA increased palmitate oxidation but did not affect its esterification. Pharmacological inhibition of AMP-activated protein kinase and etomoxir, an inhibitor of carnitine palmitoyltransferase 1 (CPT1), the rate-limiting enzyme in fatty acid ß-oxidation, attenuated the protective effect of the ELOVL2/DHA axis during glucolipotoxicity. Downregulation of CPT1 also counteracted the anti-apoptotic action of the ELOVL2/DHA axis. By contrast, a mutated active form of Cpt1 inhibited glucolipotoxicity-induced beta cell apoptosis when ELOVL2 was downregulated. CONCLUSIONS/INTERPRETATION: Our results identify ELOVL2 as a critical pro-survival enzyme for preventing beta cell death and dysfunction induced by glucolipotoxicity, notably by favouring palmitate oxidation in mitochondria through a CPT1-dependent mechanism.

Effects of meal ingestion on intramyocellular ceramide concentrations and fractional de novo synthesis in humans.

We investigated the effects of meal ingestion on intramyofibrillar (IMF) and subsarcolemmal (SS) ceramide metabolism in volunteers ranging from lean to obese. Thirty-eight women and men underwent a steady-state meal ingestion protocol that included a 6.5-h infusion of [U-13C]palmitate and muscle biopsies 1.5 and 6.5 h after starting the tracer infusion. We measured IMF and SS sphingolipid concentrations and the contribution of plasma palmitate to intramyocellular C16:0 ceramide by use of LC-MS-MS. In response to meal ingestion SS C24 ceramide concentrations, but not C14-C20 concentrations, increased significantly. IMF ceramide concentrations did not change. The increases in SS C24 ceramides were negatively related to parameters of insulin resistance. The fractional contribution of plasma palmitate to intramyocellular C16:0 ceramides in both IMF and SS fractions was inversely related to overweight status (ß = -0.432, P = 0.0095 and ß = -0.443, P = 0.0058, respectively). These data indicate that meal ingestion has differing effects on SS ceramide subspecies and suggest that the fractional de novo synthesis of intramyocellular ceramide from plasma palmitate in the postprandial condition is reduced in those who are overweight.