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Saliva is produced by both large and small salivary glands and may be considered one of the most important factors influencing the behavior of oral cavity homeostasis. Secretion of saliva plays an important role in numerous significant biological processes. Saliva facilitates chewing and bolus formation as well as performs protective functions and determines the buffering and antibacterial prosperities of the oral environment. Salivary lipids appear to be a very important component of saliva, as their qualitative and quantitative composition can be changed in various pathological states and human diseases. It has been shown that disturbances in salivary lipid homeostasis are involved in periodontal diseases as well as various systemic disorders (e.g. cystic fibrosis, diabetes and Sjögren's syndrome). However, little is known about the role and composition of salivary lipids and their interaction with other important ingredients of human saliva, including proteins, glycoproteins and salivary mucins. The purpose of this review paper is to present the latest knowledge on salivary lipids in healthy conditions and in oral and systemic diseases.

Purpose: The aim of this work was to assess the effect(s) of de novo ceramide synthesis inhibition on lipid metabolism in skeletal muscle tissue of type 1 diabetic rats. The latter seems to be of vital importance, since previous works have shown its positive influence on lipid metabolism and glucose homeostasis in the case of its counterpart - type 2 diabetes., Materials/methods: The animals were randomly assigned to one of the following groups: C - control, M - myriocin (ceramide de novo synthesis inhibitor), D - diabetes (induced by streptozotocin injections); D+M - diabetes+myriocin. We have evaluated intracellular concentration of key sphingolipid species, via chromatography (GC and HPLC), and the activity of their most important enzymes, using radiometric approach. The aforementioned assessments were evaluated in respect to the three different types of muscle tissue representing different spectra of muscle metabolism (soleus - oxidative, red gastrocnemious - oxidative-glycolytic, white gastrocnemious - glycolytic)., Results: Interestingly, our therapeutic intervention not only lowered the level of ceramide, its precursors (sphinganine) and derivatives (sphingosine and sphingosine-1-phosphate), but also reduced other lipid species (triacylglycerols, diacylglycerols and free fatty acids) content, thus improving glucose homeostasis in type 1 diabetic animals., Conclusions: In the light of the results ensuing from this study, it seems conceivable that the reduction of intramuscular ceramide production and accumulation could bestow an insulin-sensitizing effect. If so, then SPT inhibition could find potential future applications as a therapeutic intervention aimed to mitigate the effects of insulin resistance., (Copyright © 2016 Medical University of Bialystok. Published by Elsevier B.V. All rights reserved.)

Incidence of colorectal cancer (CRC) is growing worldwide. Pathogenetic mechanisms responsible for its onset and progression need further clarification. Colorectal adenomatous polyps are precancerous lesions with malignant potential dependent on histological architecture and grade of nuclear dysplasia. One of the factors conditioning CRC development are abnormalities in sphingolipid metabolism. The aim of this study was to assess the levels of sphingolipids in human colorectal adenomas. The control group (C, n = 12) consisted of patients with no colonic polyps. The examined group consisted of patients with prior diagnosed colonic polyps, qualified to endoscopic polypectomy. This group was further divided due to histological architecture into tubular adenomas group (TA, n = 10), tubulovillous adenomas with low-grade dysplasia (LGD-TVA, n = 10), and tubulovillous adenomas group with high-grade dysplasia (HGD-TVA, n = 11). In tissue samples, sphingolipd metabolite contents were measured using high performance liquid chromatography (HPLC). In cases of polypoid lesions with low malignancy potential (tubular adenomas), concentration of ceramide, which is characterized by proapoptotic and anti-proliferative properties, increases compared with control group (p < 0.05), whereas content of sphingosine-1-phosphate with anti-apoptotic and stimulating cellular proliferation properties is reduced in comparison with control group (p < 0.05). On the contrary, in cases of more advanced form of adenomatous polyps (tubulovillous adenomas with high-grade dysplasia), the ceramide level decreases compared with control group (p < 0.05) while sphingosine-1-phosphate concentration is elevated (p < 0.05). We found that concentrations of pro-apoptotic ceramide are decreased and pro-proliferative S1P levels are increased in polypoid lesions with high malignancy potential, and it was the opposite in those with low malignancy potential.

Background & Aims: Nonalcoholic fatty liver disease (NAFLD) is an insulin resistance-related hepatic disorder which can transform to cirrhosis. Insulin resistance deregulates hepatic lipid metabolism, leading to accumulation of cytotoxic lipids including ceramide and diacylglycerols. Myriocin, obtained from fungi traditionally used in Chinese medicine in an effort to attain eternal youth, is a potent pharmacological inhibitor of ceramide de novo synthesis. We examined whether inhibition of ceramide de novo synthesis with myriocin ameliorate hepatic lipid accumulation and reverse NAFLD., Methods: The experiment was carried out on male Wistar rats. The animals were divided into four groups: (i) control group, fed standard rodent diet, (ii) group, fed standard diet also treated with myriocin for 7 days, (iii) group, fed high-fat diet for 5 weeks, (iv) group, fed high-fat diet and treated with myriocin. In liver samples sphingolipids: ceramide, sphingosine and sphingosine-1-phosphatate and neutral lipids, such as diacylglycerols and triacylglycerols were measured. In peripheral blood samples, glucose and insulin levels and aminotransferases activities were measured., Results: High-fat diet feeding caused NAFLD, confirmed by histological assessment, with increased hepatic lipids accumulation and whole-body insulin resistance. After treating with inhibitor of ceramide de novo synthesis, decrease in hepatic ceramide and other toxic lipids were noticed. Moreover, histological analysis of liver samples revealed that inhibition of ceramide de novo synthesis reduced hepatic steatosis., Conclusions: Inhibition of ceramide de novo synthesis reduced hepatic lipid accumulation in rats with NAFLD, this led to amelioration of hepatic steatosis., (© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

It is known that the ratio, the level of sphingosine-1-phosphate (S1P)/the level of ceramide (CER) determines survival of the cells. The aim of the present study was to examine the effect of myocardial infarction on the level of different sphingolipids in the uninfarcted area. The experiments were carried out on male Wistar rats: 1, control; 2, after ligation of the left coronary artery (infarct) and 3, sham operated. Samples of the uninfarcted area of the left ventricle were taken in 1, 6 and 24 h after the surgery. The level of sphingolipids, S1P, CER, sphingosine (SPH), sphinganine-1-phosphate (SPA1P) and sphinganine (SPA) was determined. The control values were (ng/mg), S1P-0.33 ± 0.03, SPH-1.02 ± 0.13, SPA1P-0.11 ± 0.01, SPA-0.28 ± 0.04, total CER-20.3 ± 1.8. In infarct, the level of S1P in the uninfarcted area was reduced by ~3 times in 1 and 6 h and decreased further in 24 h. The level of SPH decreased in 1 h and returned to the control thereafter. The total level of CER decreased in 6 h after the infarction. Sham surgery also produced changes in the level of certain sphingolipids. The ratio, the level of S1P/the level of CER was markedly reduced at each time point after the infarction. It is concluded that the reduction in the S1P/CER ratio could be responsible for increased apoptosis in the uninfarcted area after the myocardial infarction in the rat.

Gelsolin is an actin-binding and an actin-fragmenting protein. It contains 730 amino-acids, organized in six G1-G6 homologous domains which determine different functions of the protein. Two variants of gelsolin, cytoplasmic and secreted (contained in plasma) are described. Cytoplasmic gelsolin re-organizes the structure of cytoskeleton and plays an important role as a capping protein. In addition, cytoplasmic gelsolin binds bacterial lipopolysaccharide and ATP and exhibits antibacterial and anti-inflammatory properties. Plasma gelsolin is synthesized mainly in skeletal and smooth muscles and myocardium. Plasma gelsolin was also found in: blood, lymph, bronchial epithelia, synovial fluids and cerebro-spinal fluid. The protein plays a role in the immune response, moreover it is involved in extracellular and blood actin-scavenger system. Plasma gelsolin has anti-amyloidogenic, anti-oxidant and anti-apoptotic properties and it has a potential for treatment of Alzheimer disease. Decreased levels of the gelsolin plasma isoform was observed in patients with sepsis, myocardial infarction, liver failure, acute respiratory distress syndrome, inflammations and after burns. On the other hand, after rhabdomyolysis and in amyloidosis gelsolin plasma level are increased. In this review we present recent data on the structure and functions of gelsolin and changes of its activity in some pathological processes.