Adropin - physiological and pathophysiological role.

Adropin is a peptide hormone that was discovered in 2008 by Kumar et al. This protein consists of 76 amino acids, and it was originally described as a secreted peptide, with residues 1-33 encoding a secretory signal peptide sequence. The amino acid sequence of this protein in humans, mice and rats is identical. While our knowledge of the exact physiological roles of this poorly understood peptide continues to evolve, recent data suggest a role in energy homeostasis and the control of glucose and fatty acid metabolism. This protein is encoded by the Enho gene, which is expressed primarily in the liver and the central nervous system. The regulation of adropin secretion is controversial. Adropin immunoreactivity has been reported by several laboratories in the circulation of humans, non-human primates and rodents. However, more recently it has been suggested that adropin is a membrane-bound protein that modulates cell-cell communication. Moreover, adropin has been detected in various tissues and body fluids, such as brain, cerebellum, liver, kidney, heart, pancreas, small intestine, endothelial cells, colostrum, cheese whey and milk. The protein level, as shown by previous research, changes in various physiological and pathophysiological conditions. Adropin is involved in carbohydrate-lipid metabolism, metabolic diseases, central nervous system function, endothelial function and cardiovascular disease. The knowledge of this interesting protein, its exact role and mechanism of action is insufficient. This article provides an overview of the existing literature about the role of adropin, both in physiological and pathophysiological conditions.

Serum levels of 12 renal function and injury markers in patients with glomerulonephritis.

INTRODUCTION    Glomerulonephritis (GN) is a complex disease that affects the function of the whole nephron. There are few data on the serum levels of the most common biomarkers of kidney function and injury in GN, or the studies provide ambiguous results. OBJECTIVES    The aim of the study was to evaluate the levels of known kidney-specific and nonspecific markers of renal function or injury in the serum of patients with diagnosed primary or secondary GN, with or without the presence of nephrotic syndrome (NS) and arterial hypertension (AH). PATIENTS AND METHODS    The study included 58 patients with diagnosed GN and 6 patients with congenital defects (CD) of the kidney and AH (CD+AH). The serum levels of ß2-microglobulin (ß2M), neutrophil­gelatinase associated lipocalin (NGAL), osteopontin, trefoil factor 3 (TFF-3), calbindin, glutathione-S­transferase- π (GST-π), interleukin 18 (IL-18), kidney injury molecule 1 (KIM-1), and monocyte chemoattractant protein 1 (MCP-1) were measured with Kidney Toxicity Panels 1 and 2 using the Bio-Plex method. Renalase levels were measured using an enzyme-linked immunosorbent assay. RESULTS    In the whole group and in the subgroups (GN, GN+AH, GN+NS, CD+AH), NGAL, KIM-1, TFF-3, IL-18, ß2M, and calbindin levels correlated with estimated glomerular filtration rate (eGFR). In patients with NS, this correlation for calbindin was reversed. Renalase, MCP-1, GST-π, and osteopontin levels were independent of eGFR. Increase in IL-18 levels in the group with GN was assiociated with lower odds of the kidney disease. When this group was divided according to eGFR into subgroups G1-G5, TFF-3, NGAL, and ß2M levels increased with the stage of the disease. CONCLUSIONS In patients with NS, renalase and MCP-1 might regulate each other's levels. Further studies are needed to investigate associations between renalase, MCP-1, and osteopontin as factors unrelated to eGFR in GN. NS may contribute to the loss of calbindin from serum. NGAL, KIM-1, TFF-3, IL-18, ß2M, and calbindin are good indicators of kidney function loss in patients with GN.

Lysophosphatidic acid signaling in ovarian cancer.

Lysophosphatidic acid (LPA) is a bioactive phospholipid that is involved in signal transduction between cells. Plasma and ascites levels of LPA are increased in ovarian cancer patients even in the early stages and thus LPA is considered as a potential diagnostic marker for this disease. This review presents the current knowledge regarding LPA signaling in epithelial ovarian cancer. LPA stimulates proliferation, migration and invasion of ovarian cancer cells through regulation of vascular endothelial growth factor, matrix metalloproteinases, urokinase plasminogen activator, interleukin-6, interleukin-8, CXC motif chemokine ligand 12/CXC receptor 4, COX2, cyclin D1, Hippo-Yap and growth-regulated oncogene α concentrations. In this article, all of these targets and signal pathways involved in LPA influence are described.

Xanthine oxidoreductase reference values in platelet-poor plasma and platelets in healthy volunteers.

INTRODUCTION: Xanthine oxidoreductase (XOR) is an enzyme belonging to the class of hydroxylases. XOR is stated, inter alia, in the kidneys, liver, and small intestine as well as in leukocytes and platelets and endothelial cells of capillaries. Its main role is to participate in the conversion of hypoxanthine to xanthine and the uric acid. It occurs in two isoforms: dehydrogenase (XD) and oxidase (XO), which is considered one of the sources of reactive oxygen species. Aim of the Study. Determination of reference values of xanthine oxidoreductase activity in PPP and platelets. MATERIALS AND METHODS: Study group consisted of 70 healthy volunteers. The isoform activities of xanthine oxidoreductase were determined by kinetic spectrophotometry. RESULTS: A statistically significant difference between the activity of the XOR in PPP and platelets (P < 0.001). The highest activity of XO was found in both PPP and blood platelets. Significant differences between the activity of the various isoforms in PPP (P = 0.0032) and platelets (P < 0.001) were also found. CONCLUSIONS: The healthy volunteers showed the highest activity XO (prooxidant) and the lowest XD (antioxidant), which indicates a slight oxidative stress and confirmed physiological effects of XOR.

[Lysophosphatidic acid and malignant neoplasms]. / Kwas lizofosfatydowy w nowotworach zlosliwych.

Lysophosphatidic acid (LPA) is a lipid compound which plays an important role in the human body, enabling its proper development and functioning. The extracellular LPA is mainly formed of lysophospholipids by the action of autotaxin. LPA activates specific G protein coupled receptors on the cell surface, which results in activation of intracellular signaling pathways, resulting in an increased production of proteins such as VEGF, MMP and uPA. The effect is increased cell proliferation, migration, survival and morphological changes. Aberrant expression of LPA receptors or autotaxin is present in various neoplasms. LPA may be used as a potential diagnostic marker, because its concentrations in the plasma of ovarian cancer patients are significantly higher than in the control group. Scientific research is focused on the searching for the compounds that inhibit the effects of LPA. The promising results of preclinical trials suggest potential usefulness of these compounds in the fight against cancer.

Methods for quantifying lysophosphatidic acid in body fluids: a review.

Lysophosphatidic acid (LPA) is a bioactive lipid involved in cellular signal transduction. LPA plays a role in both physiological and pathological processes. Elevated levels of LPA are observed in the plasma of patients with epithelial ovarian cancer, indicating its potential as a diagnostic marker. Quantification of total LPA can be performed by radioenzymatic, fluorometric, colorimetric, or immunoezymatic assay. Determination of individual LPA molecular species requires the use of capillary electrophoresis, gas chromatography, thin layer chromatography, liquid chromatography, or a matrix-assisted laser desorption/ionization time-of-flight method connected to an appropriate detection system.